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Aiming at the problems of incomplete efficiency composition, limitation to single working condition calculation and lack of power loss analysis in the current efficiency model research of hydro-mechanical continuously variable transmission（HMT）, this study establishes a full-condition efficiency model of HMT considering the power loss of transmission components and accessories. Firstly, the general efficiency model of HMT variable pump-quantitative motor is established, and the relevant parameters are recognized according to the efficiency test data; then the efficiency models of other HMT transmission mechanisms and accessories are established, and the complete HMT efficiency model is obtained by combining the efficiency models of each part. Based on the self-developed HMT, the calculation is carried out to obtain the full working condition efficiency map and the loss power of each component mechanism, the test bench is built, and the efficiency test is carried out on the HMT to validate the accuracy of the model, and the average absolute errors of the efficiencies of the HM1 section and the HM2 section under full working condition are 0.027 3 and 0.026 1, respectively, which improve the accuracy of the HM1section and the HM2 section by 64.59% and 55.46% respectively, comparing to the accuracy of the comparative methods. Combined with the efficiency diagram and power loss situation to analyze the HMT efficiency characteristics and influencing factors, the results show that: 1) the HMT efficiency model in this paper is mainly affected by the load and the displacement ratio e of the hydraulic unit, and the influence of the input speed is not significant; 2) the main influencing factors of this paper’s HMT efficiency model are the load under the low load, and the displacement ratio under the high load; 3) the power loss of the pump motor has the greatest influence on the HMT efficiency, and the hydraulic loss power is large when e ＜ 0. The HMT efficiency is low; when e = 0, the hydraulic loss power is 0, and the HMT efficiency reaches the highest; 4) the power loss of gears and clutches does not have a negligible impact on the HMT efficiency, and the consideration of the power loss of other accessories is conducive to the improvement of the modeling accuracy. Measures to improve the efficiency of HMT:1) Try to avoid HMT working under power cycling conditions for a long time, and recommend operating at purely mechanical points and their nearby work points under the premise of prioritizing load demand and ensuring engine economy; 2) Avoid prolonged low load operation, and should be kept in high load conditions; 3) Select high-efficiency hydraulic unit or improve the transmission efficiency of the hydraulic unit by improving the parameters; 4) Improve parameters to reduce power loss under the premise of meeting the performance requirements of gears and clutches. [ABSTRACT FROM AUTHOR]

Agricultural machinery dispatching operations, as an innovative model of socialized agricultural machinery services, have been widely implemented in county- or district-level administrative areas across the province. Due to the similar crop maturity periods within the same province, the demand for agricultural machinery is concentrated during peak operation periods, leading to a supply-demand imbalance where some machinery owners have no work while others have jobs but no machinery. This not only affects agricultural production efficiency but also increases the difficulty and complexity of agricultural production due to the lack of scientific and rational scheduling strategies. To address this challenge, many studies have adopted traditional heuristic algorithms to optimize the scheduling of harvester cooperative operations. However, issues such as low work efficiency and high operational costs remain. In response to these challenges, this study constructs a harvester co-scheduling model aimed at minimizing the transfer costs between fields. An inter-regional collaborative optimization scheduling algorithm based on deep reinforcement learning (DRL-ICOSA) was designed. This paper first analyzes the Markov decision process of harvester collaborative scheduling operations and constructs a deep reinforcement learning environment. For the attention mechanism, a policy network and a value network based on the encoder-decoder architecture were designed to enable the model to automatically learn the complexity of the environment, effectively utilize raw data, and improve performance and generalization capabilities. Dynamic Gaussian noise was introduced into the random sampling strategy to prevent the policy network from falling into local optima during the initial training stage while enhancing the model's performance and robustness. The model was effectively trained using a proximal policy optimization algorithm. Finally, the trained model was validated on a farmland test set, and the optimal path was selected using a greedy action selection strategy, resulting in an optimized solution for cross-county harvester scheduling. To verify the algorithm's effectiveness, four combined operation scenarios were considered, based on effective operation durations of 40 and 24h, with the agricultural machinery scheduling center located at the center and edge of the operation area, respectively. The DRL-ICOSA algorithm, genetic algorithm (GA), particle swarm optimization (PSO), and simulated annealing (SA) were used to calculate scheduling strategies and conduct comparative analysis. The experimental results indicate that: when the scheduling center is located at the center or edge of the area and the effective operation duration is 40h, the DRL-ICOSA algorithm reduces the average scheduling cost by no less than 13.9% compared to the GA, PSO, and SA algorithms; when the effective operation duration is 24h, the average scheduling cost reduction is no less than 11.5%. when the operation duration is 40 or 24h and the scheduling center is located at the center of the area, the DRL-ICOSA algorithm reduces the average scheduling cost by no less than 12.3% compared to the GA, PSO, and SA algorithms; when the scheduling center is located at the edge of the area, the average scheduling cost reduction is no less than 11.5% for the DRL-ICOSA algorithm compared to the GA, PSO, and SA algorithms. Therefore, regardless of the effective operation duration or the geographical location of the scheduling center, the DRL-ICOSA algorithm consistently achieves the lowest scheduling cost compared to the other three algorithms. In summary, this study provides a more scientific and reasonable scheduling solution for the complex problem of collaborative harvester scheduling operations. The DRL-ICOSA algorithm demonstrates outstanding effectiveness in reducing scheduling costs and shows significant potential and application value in addressing the optimization problem of collaborative harvester scheduling. Compared with traditional heuristic algorithms, the proposed method is more suitable for complex environments and possesses stronger generalization capabilities. It avoids the manual feature design steps of traditional methods, thereby reducing dependence on prior knowledge. This study can effectively reduce resource waste and cost expenditure. [ABSTRACT FROM AUTHOR]

Cultivation and sowing agricultural machinery equipment plays a pivotal role in influencing the quality and efficiency of cultivation operations across 133 million hectares of arable land in China. The rapid advancement of agricultural mechanization has led to heightened demands for enhanced wear resistance and extended service life of soil-engaging components in cultivation and sowing agricultural machinery, including rotary tillers, plowshares, deep loosening shovels, rake blades, and trenchers. Consequently, there is a paramount need to bolster research efforts aimed at enhancing the surface wear resistance of soil-engaging components in agricultural machinery and equipment. Building upon this premise, this study provides a comprehensive overview of the current research status regarding the enhancement of surface wear resistance in soil-engaging components within agricultural machinery and equipment. Initially, the primary forms of wear and failure in soil-engaging components of agricultural machinery and equipment are elucidated, encompassing abrasive wear, fatigue wear, and corrosion wear. Concurrently, the wear mechanisms of soil-engaging components in agricultural machinery, influenced by external factors such as abrasive particle shape, external load, soil moisture content, and pH value, are delineated, alongside an overview of diverse research methodologies concerning these mechanisms. Subsequently, detailed elaboration is provided on the progress in research and development of surface treatment processes, including surface melting, welding, thermal spraying, laser surface strengthening, chemical heat treatment, and brazing. Furthermore, an exploration and analysis of the disparity in wear resistance and strengthening technology for soil-engaging components between China and foreign nations are conducted from four perspectives: wear mechanism, material research and development, structural design, and manufacturing processes. Although domestic enterprises and researchers have conducted significant research, a noticeable disparity persists between soil-engaging components in domestic tillage and broadcasting equipment and their foreign counterparts. The research and development system remains imperfect, and there is a misalignment between promotion and application, thus hindering the formation of an internationally competitive industry chain for wear-resistant soil-engaging components. Finally, addressing the current challenges and deficiencies in the failure mechanisms, materials, structures, and processes of soil-engaging components in tillage and sowing machinery, this paper discusses the research and development directions aimed at enhancing wear resistance in agricultural machinery and equipment. 1) Enhance research on the wear resistance of soil-engaging components in diverse operational environments of tillage and sowing machinery; 2) Utilizing tribological theory, analyze the interaction laws of "environment, component, and material," thereby intensifying the development and research of substrate and coating materials for soil-engaging components; 3) Improve the optimization design of soil-engaging component structures to fulfill requirements for wear resistance, longevity, drag reduction, and lightweight properties; 4) To ensure the synchronized attainment of precision, strength, toughness, wear resistance, and prolonged service life in soil-engaging components, research on the process system of such components will be fortified, thereby furnishing theoretical foundations and technical support for research and engineering applications pertaining to enhancing surface wear resistance. [ABSTRACT FROM AUTHOR]

Cotton, one of the main commercial crops in the world, mostly distributes in several major growing regions, including Xinjiang of western China. An important renewable biomass resource, the cotton stalk has received most attention to serving as the poultry feed, paper making, environmental protection materials, and biomass briquette fuel. Particularly, the highly efficient recycling of cotton stalk can be widely expected to bring enormous economic and ecological benefits. However, most previous treatments are focused on pulverizing cotton stalks and returning to the field. A great challenge is still posed on the current pulling machines for cotton stalks, with emphasis on operational requirements, leakage, and breaking rate. In this study, a novel horizontal-roller cotton stalk pulling machine was proposed to efficiently implement the pulling of the whole cotton stalk after harvesting. The machine was mainly composed of traction, gearbox, stalk conveying, transmission system, machine body, road wheel, spacing regulating mechanism, stalk pulling, dam-board, and support frame. Specifically, the power input shaft of the gearbox was connected to the power output shaft of a tractor. In working, the power was transferred to the chain drive by the power output shaft of a gearbox, and then to realize the stalk conveying and pulling operation under the rotation of the toothed belt and the opposite rotation of the stalk pulling roller. A systematic kinematic analysis was conducted to determine the influencing factors in the working process. A field test was also carried out in a farmland in Korla City, Xinjiang Uygur Autonomous Region of China in October 2019. The soil firmness was 467 kPa, and the moisture content of the soil was 15%-20%, due to the perennial drought and little rain in the study area. The average height of cotton stalk was 700 mm, while, the plant spacing was 50 mm in a wide and narrow close planting mode. The power was from a CFD604A wheeled tractor with a calibrated power of 44.2 kW. The test was performed on the national standard of a harvester combine test(GB/T 8097-2008). A three-level quadratic regression orthogonal test was designed, where the forward velocity of the machine, the rod velocity of the deflector, and the speed of the stalk pulling roller were selected as the influencing factors, whereas, the leakage rate and plucking rate were the response factors. A response surface method was utilized to establish the regression equations for the relationship between the factors and assessment indexes. An optimal combination of parameters was obtained, while an experiment was also conducted to verify the mathematical model. The test results demonstrated that there were great effects of factors on the performance of horizontal-roller cotton stalk pulling. The significant effects on the leakage rate were ranked in a decreasing order: the forward velocity of the machine, the rod velocity of the deflector, and the speed of the stalk pulling roller. Correspondingly, the significant effects on the plucking rate were ranked in a decreasing order: the speed of the stalk pulling roller, the rod velocity of the deflector, and the forward velocity of the machine. The verification test indicated that the leakage rate of the cotton stalk was 5.24%, and the plucking rate was 3.75%,when the forward velocity of the machine was 0.68 m/s, the rod velocity of the deflector was 1.75 m/s, and the speed of the stalk pulling roller was 221 r/min. The optimal combination was better consistent with the predicted one in model optimization, indicating a reasonable structural design. The findings can provide a sound reference for the structural design and optimization of operation parameters in the horizontal-roller cotton stalk pulling machine. [ABSTRACT FROM AUTHOR]

Landscape patterns have been integrated into the crop planting process, thereby developing the potential ornamental value of field crops, such as rape and wheat. A seed tape-weaving machine can be used to knit the seeds of crops into a specific paper tape for mechanized or ornamental planting. In this machine, the seeds are sucked into the paper tape at a constant speed via a vacuum pump, where the paper tape is bound together with biodegradable cotton thread. In this study, an improved weaving machine of seed tape was designed to mix the rape-wheat seeds for a landscape. The pattern automatically realized the regular arrangement of rape and wheat seeds in the seed tape. The key components were also designed for the typical weaving process of mixed seeds, including the air-suction seed-metering device and seed guiding tubes. Taking the commercialized rape seeds of Zhongshuang No.9 and wheat seeds of Zhengmai No.9023 as the test objects, four types of experiments were conducted: the seed metering performance test, the paper feeding accuracy test, the pattern weaving performance test, and the field test. The structural and operating parameters were also optimized for the better weaving effect in the improved weaving machine of seed tape. In the seed metering performance, the results showed that the main influencing factors were the negative air pressure, followed by the diameter of suction holes, and the motor speed in the air-suction type seed metering device. In rape seeds, the air-suction type seed metering device worked on the condition with the negative air pressure of 2 500 Pa, the suction hole with a diameter of 1.2 mm, and the motor speed of 3 r/min. In wheat seeds, the better seeding performance was achieved, where the airflow negative pressure of 2 500 Pa, the suction hole with the length of 3.9 mm×1.9 mm, and the motor speed of 3 r/min. Specifically, the seeding qualification rate was 94.1% and 92.2%, the multiple rates were 1.8% and 3.1%, and the miss seeding rates were 4.1% and 4.7%, for the rape and wheat seeds, respectively, indicating that both seed metering devices achieved the best seeding performance. The weaving performance test showed that: i) There were good uniformity and even quality of paper feeding, where the variation coefficient of plant spacing was less than 6%; ii) When the total number of weaving points gradually increased in the range of 100 to 900, the variation coefficient of relative position in the pattern decreased first, then stabilized, and finally stabilized at about 17%; iii) The variation coefficient of weaving area first decreased and then stabilized, and finally stabilized at about 8%; iv) The accuracy of pattern weaving gradually increased, and then stabilized. The field test was performed on a 30×30 size pattern of five points star in a square. The results showed that the variation coefficient of relative position in the pattern was 18.26%, and the variation coefficient of weaving area was 10.87%. A better visual effect was achieved in the formed pattern. The improved weaving machine can be expected to improve the work efficiency, while reducing labor intensity and error probability, for the mechanized planting of field crops in landscape patterns. The findings can provide a new idea and solution for the modeling and implementation of landscape patterns with field crops, like rape and wheat, further to promote the development of rural tourism in China. [ABSTRACT FROM AUTHOR]

In north China, the ploughing operation of high-power tractor based on electro-hydraulic suspension system is the most common and important agricultural process in the field agricultural production. Due to the complex field working environment, the change of tillage depth and the fluctuation of soil specific resistance, the working load of tractor unit fluctuates greatly during ploughing operation, which is easy to cause excessive sliding of driving wheel， and seriously affects the traction efficiency and traction of the operation unit. In order to solve the problem of excessive driving wheel slip of high-power tractor for ploughing, taking the high-power tractor ploughing unit with electro-hydraulic hitch system as the research object, a sliding rate control method based on sliding mode variable structure control was proposed this paper. Firstly, in view of the strong nonlinear characteristics of the complex system of "tractor-farm tools-soil", the nonlinear dynamics model of tractor driving wheel sliding for ploughing was established based on tractor motion characteristics and the theories of vehicle dynamics. Then, the exponential reaching law was used to design the sliding rate nonlinear control algorithm based on sliding mode variable structure control theory. Especially, taking the hydraulic pressure of hydraulic cylinder as the equivalent control quantity, the control law of sliding mode variable structure control was derived after simplifying the hydraulic system. Through MATLAB/Simulink simulation, the reliability of the nonlinear dynamic model and control algorithm in the step change of soil specific resistance was verified. According to the soil data obtained from a specific site, the soil specific resistance was set as pulse signal, and the stable value was 30 000 N/m². At the beginning of the simulation, a soil specific resistance with an amplitude of 8 000 N/m², a period of 10 s and a duty cycle of 50% was added to block the impulse signal. The results showed that the slip rate of the driving wheel was always near the sliding surface, the steady-state error was 0.002, and the control overshoot was 0.008. Furthermore, the field test platform for automatic slip rate control system was built on Lovol-TG1254 tractor, and the field comparison tests between SMVSC control and Fuzzy PID control were carried out under the tractor speed of 2.17 m/s. The test results showed that compared with the fuzzy PID control, the mean absolute deviation of slip rate under the SMVSC control decreased by 27%, the maximum deviation decreased by about 49%, and the fluctuation range and control deviation of slip rate were smaller. The change of depth was 5.26 cm, which decreased by about 27% compared with that of the fuzzy PID control, the change of hydraulic cylinder displacement was 1.15 cm, which decreased by about 36%, and the adjustment change of traction was 1 293.35 N, which decreased by about 42%. The control deviation of the driving wheel sliding control method proposed in this paper was small, it can provide theoretical basis and technical support for improving the quality of ploughing operation. [ABSTRACT FROM AUTHOR]

High-clearance plant protection machine plays an important role in the large-scale chemical fertilizer spraying machinery in China. The wheels of high-clearance plant protection machine must be driven along the ridge during the working process. However, the driver's vision is blocked by corn plants, which is easy to cause corn seedlings damaged by tires. In view of the serious phenomenon of seedling injury during the operation of high-clearance plant protection machine, a method of real-time extraction of navigation line between the corn rows based on a dynamic Region of Interest (ROI) was proposed in this paper. According to the different growing periods of corn, the videos were collected when the average height of corn plant was 30, 50 and 70 cm under different light conditions. Through reducing the influence of light by pixel normalization, segmenting the image of corn and background by green image processing algorithm and the maximum class square error method, the images were enhanced and removed by morphological processing. Firstly, the collected image was divided into 10 image bands, and each image band was processed by vertical projection method to locate the center lines between crop rows in the first frame of the video. The approximate position of the static ROI was determined and marked based on the perspective principle of camera and geometric information of the corn seedling belts. It took 473.7 ms to divide the static ROI, which does not affect the real-time performance of navigation since the determined of static ROI was prior to the navigation operation. Secondly, the static ROI was applied in the second frame of video, in which the navigation line between the corn rows was obtained by sub-regional feature points clustering algorithm. According to the geometric information of navigation line and ROI, the ROI was updated and optimized. Then the updated ROI was applied to the navigation line extraction of the next video frame. 225 consecutive videos were selected to divide the ROI manually, and the dynamic ROI obtained by proposed method was compared with the artificial ROI. The pixel deviation between the artificial ROI and the ROI was about 10 pixels, which shown that the algorithm had good convergence and met the requirements of navigation accuracy. Finally, a comparative experiment of artificial navigation line extraction and the algorithm in this paper by randomly selecting 100 frames of image. The results showed that the algorithm proposed by this paper could automatically obtain the dynamic ROI, the average error of navigation line extraction between manual and algorithm in this paper was 1.157°, and the accuracy rate of corn seedling belt recognitionwas 96%, and the average processing time of a real-time image with a resolution of 1 920 pixels×1 080 pixels was 97.56 ms. July 16, 2019, the navigation experiment was carried out in corn field, and the heading angle was used as the input signal of the automatic steering control system. The results showed that the wheels of high-clearance plant protection machine walked along the corn rows, and the wheel angle floated up and down at 0°. The algorithm proposed in this paper can meet the accuracy and real-time requirements of the automatic walking for high-clearance plant protection machine in corn. [ABSTRACT FROM AUTHOR]

: In order to monitor illegal land use in real time, video surveillance technology was used to monitor the vulnerable areas of illegal land use. Excavator was one of the most important construction machinery in the engineering construction, an automatic real-time detection of excavator could provide important information for non-contact field monitoring of illegal land. But it was difficult to accurately detect the excavator due to the complex background, uneven illumination and partial occlusion in natural scene, This paper proposed a real-time excavator detection algorithm in natural scene based on the SSD-like (Single Shot Detector). Specifically, the lightweight network DDB (Depthwise Dense Block) was used as the basic network to extract shallow feature and fuse with high-level features in the excavator objection model to enhance the feature representation capability. Meanwhile, the BDM (Bottleneck Down-sampling Module) which was designed based on the lightweight network MobileNetV2 was used as the multi-scale feature extraction network to reduce the parameter quantity and computation. The data sets included 18 537 images of excavators with different shooting angles and natural scenes, 15 009 images were used as training set and 3 528 images were chosen as test set randomly. To enhance the diversity of training data, data set expansion methods such as rotation and image were adopted. Based on the Caffe deep learning framework, the proposed model in this paper was trained with end-to-end approximate joint methods and the model weight was fine-tuned by using SGD (Stochastic Gradient Descent) algorithm. The DDB module of the network was initialized with the weights pre-trained on the PASCAL VOC dataset, and the training time and resources were further reduced by transferring learning. Then the model pre-trained on the large data sets was transplanted to excavator object detection by transfer learning. The proposed method was transplanted and performed on the mainstream Jetson TX1 embedded hardware platform, and experiments on the actual data set of detecting excavator object at different angles of view and natural scenes. Experiment results showed that the parameter quantity and computational complexity of proposed model with BDM was reduced by 68.4% compared to SSD, the mAP (Mean Average Precision) of proposed method reached 90.6% on the testing set, which was 0.4% and 0.4% higher than that of SSD based on VGG16 basic net and MobileNetV2SSD based on MobileNetV2 basic net, respectively. The model size of propose method was 4.2 MB, which was about 1/25 and 1/4 of SSD and mobilenetv2ssd, respectively, and the time-consuming of each frame was 145.2 ms, which was 122.7% and 28.2% faster than SSD and MobileNetV2SSD, respectively. The proposed method not only had better generalization and robustness, but also can be better deployed on the embedded hardware platform which demonstrated the feasibility of real-time monitoring of the excavator at site of illegal land use. [ABSTRACT FROM AUTHOR]

The existing oil sunflower threshing device cannot meet the requirements of oil sunflower threshing under different conditions. Aiming at the problems of the low oil sunflower threshing rate and the high breaking rate during the threshing process, a threshing device of oil sunflower with variable clearance based on multi-bar mechanism is designed in this paper. The structure and the working principle of the oil-sunflower threshing device with variable clearance were introduced, and the mechanisms of kinematics of the clearance adjustment mechanism and angle adjustment mechanism of the structure of variable clearance concave screen were analyzed, the motion trajectory analysis and solution were performed to determine the structural parameters, the variable clearance range of the variable clearance concave sieve was 20-60 mm. A test bench of the oil-sunflower threshing device with variable clearance was developed. The threshing test was completed at the Key Laboratory of Innovation Design Laboratory of Xinjiang Agricultural Engineering Equipment. The test object was oil sunflower No. 31 with the disk diameter of 180-220 mm and the disk thickness of 25-40 mm, the weight of single sunflower disk was 300-380 g, the moisture content of the sunflower disk was 29.59%. The test was performed according to the GB/T5982-2017 thresher test method and the DB37/T2878.2-2016 technical requirements. The orthogonal experiment of three factors and three levels was carried out, threshing rate and breaking rate were taken as the indexes and the cylinder speed，the threshing clearance as well as feed rate were the factors. The test results showed that during the threshing process, the factors that affect the oil sunflower threshing rate and breaking rate are threshing clearance, drum speed and feed rate. The optimal combination of operating parameters was that the threshing clearance 35 mm, the drum speed 280 r/min and the feed rate 1.8 kg/s. Through the analysis of variance, it was concluded that the threshing clearance had a very significant effect on the oil sunflower threshing rate and breaking rate, the drum speed was significant, and the feed amount was not significant. Multiple repeated tests were performed under a better combination of operating parameters. The test results showed that the average threshing rate of oil sunflower was 99.01%, and the breaking rate was 2.28%, which met the national standards that the threshing rate greater than 98 % and the breaking rate less than 5%. The better operating parameters of this study are only applicable to the material conditions tested in this paper, but the oil sunflower harvesting operations are complicated, and the factors such as oil sunflower varieties, moisture content, and output are also different. Adjusting the diameter of the threshing concave plate sieve, changing the threshing clearance and other working parameters is to meet the requirements of oil sunflower threshing under different conditions. The research results can provide reference for the design of subsequent oil sunflower threshing device. [ABSTRACT FROM AUTHOR]

Non-till farming has attracted increasing attention in developing sustainable agriculture, but the straws and the stubbles left over after harvest could block dispatch of fertilizer and seeds in seed drilling, which could detach the seeds and soil and result in nonuniform seed drilling both vertically and horizontally. Therefore, developing devices able to clean and crush the corn straw on seedbed before fertilization and seed drilling/spraying are demanded. However, the existing blade in such devices for laterally cutting the stubbles cannot completely clean and transport the stubble. The leftovers in soil make seed drilling problematic as they could block seed dispatch, increase energy consumption and, under certain circumstances, even make the sowing device unbale to operate. In order to resolve these problems, we designed a device to laterally cut and remove the stubbles from corn field. In this paper, we analyzed its efficacy in stubble clearance, soil disturbance, energy consumption, as well as conveying and throwing the cut/cleaned stubbles. The optimal structure of the stubble-cleaning blade and the working parameters of the device were calculated by taking the bending angle of the blade α, the transverse cutting edge B, and the angular velocity of the blade ω as determinants, and the stubble clearance ratio, soil disturbance ratio and equivalent energy consumption of the blade as quantitative indexes of its performance, using the three-factor and three-level orthogonal test and the fuzzy comprehensive evaluation method. The results showed that the stubble clearance ratio was significantly impacted by the bending angle, while the performance indexes were significantly impacted by the width and angular velocity of the blade. The factors that affected the performance of the device were ranked in the order of bending angle > transverse cutting edge > angular velocity. It was also found that soil disturbance ratio was mostly impacted by the transverse cutting edge, followed by the bending angle and the angular velocity, while the equivalent energy consumption was mostly affected the transverse cutting edge, followed by the bending angle and the velocity of the cutter tooth angle. The optimized results for the device operation were that when the operation speed was 7.2 km/h, the bending angle was 0.86 rad, the transverse cutting edge was 50 mm, and the angular velocity was 52 rad/s, the associated stubble clearance ratio was 94.3%, soil disturbance ratio was 54.3%, and the equivalent energy consumption was 3.4 kW. Under these conditions, clogging and straw entanglement did not occur. The results in this paper are helpful for designing devices to clear straw and stubbles left over after harvest in no-till farming. [ABSTRACT FROM AUTHOR]

As the core technology of mechanized conservation tillage, no-tillage sowing is a new type of agricultural cultivation method popularized in recent years, it directly sows in the field where the straw and roots of the former crops are left, which not only reduces water evaporation and soil erosion, but also can ensure the germination and growth of seeds, which is conducive to water storage and conservation, increasing production and income, and at the same time improving soil fertility to some extent. However, after the harvest of the former crops without any collection and removal treatment, the “full amount of straw field” has become the new normal state of China's cultivation. The traditional no-tillage seeding equipments are prone to easily increase the workload of straw crushing device when it entering the soil and extinguishing stubble, which causes the blockage and jamming of straw conveying device. In order to solve this problem, the back-throwing type no-tillage straw smashing planter was taken as the research object in this paper, and an automatic control system based on off-ground height of the straw smashing device was developed. Torsional deformation acquisition device was created based on a double fan-shaped through hole metal detection disc and proximity switch, which was installed at both ends of the driving shaft to effectively monitor the rotation speed of the driving shaft and the stagger angle caused by the change of torque load. The design was based on the 32-bit ARM CortexTM-M3 core microprocessor hardware platform, which constituted the data acquisition and output drive unit of the automatic control system, the driving shaft rotation speed and stagger angle was collected in real time, the change trend was analysed through the system software, and current working conditions was identified. According to the corresponding output control signal, the straw height adjusting mechanism timely corrects the off-ground height of the straw smashing and conveying device to stabilize the working load. The straw height adjustment mechanism was composed of a solenoid valve, a hydraulic cylinder, a fixed bracket and a supporting ground wheel. The hydraulic cylinder's high pressure driving oil was taken directly from the working tractor to improve the applicability of the device. The performance verification test showed that under the driving shaft’s rated rotation speed of 2 500 r/min, when the height of the straw crusher off the ground changed the working load, the automatic control system controled the rotation speed of the driving shaft between 2448 and 2632 r/min, the change of the stagger angle of the driving shaft was ± 0.002 4 rad, and the response delay time of the control signal to the change of the stagger angle was 0.24 s. The field operation comparison test showed that when the back-throwing type no-tillage straw smashing planter was equipped with automatic control system based on off-ground height of the straw smashing device, the passability of the machine was greatly improved, the occurrence of blockage was eliminated, the operation efficiency was increased by 52.9%, and the height of surface stubble was reduced by 43.4% after straw smashing operation. In conclusion, The design of this paper uses the change trend of the driving shaft rotation speed and stagger angle to identify the working condition, effectively eliminating the influence of mechanical structure parameters and material differences, and the mechanical structure is light and easy to install, which can provide reference for qualitative monitoring of torque load of agricultural machinery. [ABSTRACT FROM AUTHOR]

Thinning is one of the three labor-consuming sections (pruning, thinning and harvesting) in orchard management process. Chemical thinning, not only unstable but also reduces fruit safety, has been banned gradually in recent years. Pure artificial thinning, especially artificial fruit thinning, needs larger workload and higher labor cost, unsuitable seriously for the requirements of modern orchard planting. Two kinds of pear mechanical flower thinners were designed in the paper. They were three arms tractor-mounted flower thinner (TMFT) and hand-held flower thinner (HHFT), to alleviate the heavy labor pressure in the process of thinning and improve the efficiency of orchard operation. The width of TMFT was controlled by hydraulic cylinder that range from 1.2 to 1.7 m. TMFT rotation speed of thinning shaft that range from 0 to 300 r/min was controlled by electronic governor. The length of HHFT can change through adjusting the extension rod that range from 0.95 to 1.6 m. HHFT rotation speed of thinning shaft that range from 0 to 900 r/min was controlled by electronic governor too. ‘Y’ trellis ‘Cuiguan’ pear was taken as the research object in the paper. TMFT impact forces of thinning rope with different rotation speed of thinning shaft and thinning distance were measured in bench test, to find the working range of rotation speed. Field test setting 50% flower bud preserved rate (it is easier to thin flower buds than flowers) and 0.44 m/s tractor work speed, and the best rotation speed of thinning shaft was ensured: 254 r/min. Flower bud reserve rate, fruit set rate, work efficiency, fruit yield and quality of four kinds of operation methods were tested, which were TMFT combined with artificial fruit thinning, HHFT combined with artificial fruit thinning, artificial flower fruit thinning and artificial fruit thinning only. Twenty-four ‘Y’ trellis pear trees (6 a) with almost same size were selected for four operation methods. The canopies of each tree were divided into the upper middle lower three layers and five branches were selected as samples in each layer. In order to reduce the operation error, except the TMFT, the operation of each group was completed by two workers with experienced job skill. Field test show that three flower thinning methods can meet the requirement of 50% flower bud preserved rate, the coefficient of variation all less than 15%. There is no obvious difference between TMFT and artificial method in thinning quality and the stability of TMFT is the highest among test groups. Mechanical and artificial flower thinning can significantly reduce about 50% absolute fruit set rate. TMFT will damage the young fruits in a certain degree, but does not affect the yield and quality in the last. Work efficiency of TMFT was highest among flower thinning methods and 66.17% artificial fruit thinning time can be saved. TMFT has a higher requirement for pear orchard mechanization degree, suitable for large-scale mechanized pear orchard. Work efficiency of HHFT is second only to TMFT, 37.26% artificial fruit thinning time can be saved. HHFT is suitable for small and medium sized pear orchard. For fruit yield and quality, total and high quality fruit yield per tree of pure artificial fruit thinning group is higher 11.37% and 8.59% respectively than average values of three kinds of flower thinning group, but the average weight of high quality fruit and brix of sugar solids of is lower 6.58% and 1.55% respectively. The research is helpful to improve the working quality of flower thinner and provide reference for the mechanization management of pear orchard. [ABSTRACT FROM AUTHOR]

Moisture content is one of the important indicators in grain harvesting, trading, storage and processing. High moisture content will lead to a series of problems of grain such as mildew, deterioration, shortened storage time, lower transaction price and higher processing cost. With the development of precision agriculture, accurate detection of grain moisture content can also accurately assess the growing situation of crops, and then provide guidance for the next season’s crop planting. Compared with the drying method, the capacitance method and the electric resistance method, the microwave method is easy to realize the non-destructive measurement of the grain moisture content, which is an important direction of moisture content detection. In the field of on-line detection of moisture content of rice and wheat in combine harvesters, foreign related research started earlier, and enterprises have commercialized, but this technology is still in the research stage in China. Aiming at the problem that the rice-wheat combine harvester is difficult to accurately measure the moisture content of wheat and rice during harvesting operation, this paper studied a non-destructive on-line detection method of grain moisture content based on microwave reflection method, established the grain moisture content measurement model, designed a non-destructive on-line detection device for grain moisture content used on rice-wheat combine harvesters. The device used a 450 MHz microwave measurement module to measure the moisture content of rice and wheat non-destructively. The voltage conversion circuit was designed to convert microwave parameters into voltage signals, and the average filtering algorithm was used for signal filtering to reduce the impact of interference factors. Finally, the moisture content detection model of rice and wheat, which was established by the calibration experiment, was used to calculate the moisture content. The calculation result was displayed on the display in real time via CAN bus communication. Due to the insufficient installation space in rice-wheat combine harvester, the structure of the detecting device was designed and optimized, and the circuit portion and the sampling mechanism were integrated in a compact structure. Based on the above theoretical research, technology development and structural design, this paper carried out laboratory static experiments and field harvesting experiments. The laboratory static experiment used rice and wheat to illustrate the establishment process of the grain moisture content detection model: 30 groups of rice and 30 groups of wheat samples were prepared, moisture contents and voltages calibration experiment was completed, the rice and wheat moisture content detection models was established and the experimental results were analyzed. The field harvesting experiment was verified the practicability and reliability of the grain moisture content detecting device with rice as the test object. The experiment results show that the performance standard deviations of the laboratory static experiment and the field harvest experiment are 0.458 3 and 1.078 0, respectively, and the relative error are around 2.5% and 5%, respectively. Moisture content measuring range of the detection device for rice and wheat is 14%-34%, which meets the project requirements. [ABSTRACT FROM AUTHOR]

Along with the continuous development of agricultural aviation application technology, an agricultural unmanned aerial vehicle (UAV) is widely used in modern agricultural production, which is the operation platform for implementing agricultural aviation technology. Due to the characteristics of simple operation, simple structure, easy maintenance and low cost, electric multi-rotor UAV is widely used in the field of agricultural aviation. However, it has the problems of small load capacity, short continuous operation time, low operation efficiency, etc. The multi-rotor single-arm tandem structure can effectively improve the load capacity and operation capacity of the electric UAV, but the structure will lead to the increase of the size and mass of the whole machine and reduce the effective utilization rate of energy, which still needs to be optimized and improved. Rotor spacing affects the overall performance of multi-rotor single-arm tandem electric UAV, but the influence of different rotor spacing on rotor lift of multi-rotor single-arm structure has not been studied. In this paper, by setting up a test platform and taking power consumption (P) and lift (F) as test indexes, the rotors with different spacing were tested, and the optimal spacing ratio between tandem rotors was analyzed and determined. The optimal spacing ratio was verified by theoretical analysis and flight test of solid aircraft. The lift performance and energy consumption of coaxial and tandem twin rotors at different spacing were tested. The results showed that the longitudinal spacing ratio had no effect on the lift performance, while the lateral spacing ratio had an effect on the lift performance. In order to further determine the optimal lateral spacing ratio, the variation law of rotor lift with lateral spacing ratio under the double rotor tandem arrangement was tested. When the lateral spacing ratio was less than 1.8, the lower rotor lift increased with the increase of lateral spacing ratio under the same power consumption. When the lateral spacing ratio was greater than 1.8, the lift of the lower rotor tended to be stable, and the average value of the lower rotor lift relative to the loss percentage of the isolated rotor was stable within 0.70%. When the lateral spacing ratio was equal to 1.8, the average loss percentage of the rotor lift under the tandem layout was 0.66% relative to the isolated rotor lift under different power consumption. At this time, the lower rotor lift is basically the same as the isolated rotor lift, thus determining that the optimal spacing ratio of the tandem double rotor was equal to 1.8. Secondly, by testing the variation of the lift force of two rotors with different sizes and the rotor lift force with the lateral spacing ratio under the tandem layout of multiple rotors, it was concluded that 1.8 was suitable for the tandem layout mechanism with different sizes and number of rotors. In order to validate the optimal effect of the lateral spacing ratio of 1.8 on the rotor spacing of the multi-rotor single-arm tandem electric UAV, this paper compared and analyzed the performance parameters of planar and tandem aircraft of six-axis 12-rotor UAV with multi-rotor single-arm structure. The results showed that compared with the tandem model with lateral spacing ratio 1.8, the fuselage size of the planar model increases by 38.70%, while the lift difference between the two is only 1.52%. Through flight tests, the results showed that under the same load, the hovering power per unit time of the planar model decreased by only 0.06%, while the fuselage mass increased by 6.82% compared with the optimized tandem model, the fuselage size increased by 38.7%. This paper studied the optimal rotor spacing of multi-rotor single-arm electric UAV. On the premise of ensuring the energy efficiency of the UAV, the rotor spacing of the multi-rotor single-arm structure electric UAV is optimized by changing the relative positions between the rotors, so as to optimize the fuselage size and mass, improve the aerodynamic characteristics of the multi-rotor single-arm structure UAV, reduce inertia, enhance payload capacity, and thus improve the overall performance. [ABSTRACT FROM AUTHOR]

In the rice area of the Northeast China, the large amount of rice straw with low moisture content is tough to chop. However, the existing method of chopping combined auxiliary slitting could not meet the requirements of chopping under such condition, which could cause some problems such as incomplete straw crushing and unqualified rate of straw crushing. It would affect the subsequent land preparation and transplanting operations and caused problems such as machine blocking, straw floating before transplanting and seedling floating during transplanting. In order to solve these problems, this paper designed a straw chopper based on the principle of differential sawing, which could realize the same direction with different speed between the saw disc blade and the crushing knife to achieve supporting sawing. The friction force and relative linear velocity of crushing straw were increased to improve the crushing effect. Structural parameters of saw disc blade, crushing knife and other key components were designed through theoretical analysis, and the structure and operating parameters of the machine were preliminarily obtained. In order to improve the wind velocity and straw feeding performance of the crushing chamber, three kinds of fan blade forms, namely facade fan blade, reverse fan blade and diverse fan blade, were designed to compare with no fan blade through simulation analysis. Simulation results by Fluent showed that the facade fan blade could improve the wind velocity in the crushing chamber and contributed to improving straw fluidity, and the verification test was in accordance with the simulation results. According to the movement track of crushing knife and saw disc blade, the rotation speeds of them were designed. The rotation speed of crushing knife ranged from 1815 to 2475 r/min, accordingly, and the saw disc blade rotation speed ranged from 605 to 825 r/min, to be specific, the ratio of rotation speed between saw disc blade and crushing knife was 1/3 constantly. The dynamics analysis of straw crushing process showed that rotation speed of crushing knife and the tilt angle between the saw disc blade could affect crushing performance. Therefore, a field experiment of two factors with three levels was designed by using the average length of straw crushing and the crushing qualification rate as an evaluation index. The test results showed that the crushing knife rotation speed and angle of slope had a significant impact on average length of straw crushing and straw crushing qualification rate. Considering straw crushing performance and energy consumption, the optimal combination was determined as follows: The crushing knife rotation speed was 1800 r/min and the angle of slope was 65°, the corresponding saw disc blade rotation speed was 600 r/min. The field test results under the optimized combination conditions were as follows: the average length of straw crushing was 9.58 cm, the proportion of straw under 10 cm was 93.23%, and the scatter unevenness was 20.89%, which met the quality requirements of straw crushing and scattering in the northeast rice region. In the paper, a comparison test between the differential sawing rice straw chopper and the ordinary straw chopper was carried out. The filed test showed that the average length of straw crushing of the ordinary straw chopper was 13.42 cm, and the proportion of straw under 10 cm was 71.5%, which was not as good as the differential sawing rice straw chopper, and there was no obvious difference in the scatter unevenness between them. After the chopping operation, the same plow was used for the plowing operation, and the straw burying rate was 98.92% of the differential sawing rice straw chopper while the ordinary straw chopper was 90.21 %. Its successful implementation could greatly improve the operation effect for chopping rice straw and stubble on one hand, and on the other hand provided better growing surface conditions for rice. The design of the machine provided a basis for the popularization and application of straw mulching technology in northeast China. [ABSTRACT FROM AUTHOR]

In order to develop a more efficient and universal flower auto-transplantation technique, an auto-transplantation mechanism with the integrated function of seedling pick-up and transplanting has been designed. This mechanism involves gear driving and two transplanting arms of the same structure. The gear driving system is made up of one semi-circle gear, four oval planet gears and concave-convex lock-up arc. It aims to move with the non uniform speed through the operation of planet gears and pulling and imbedding of concave-convex lock-up arc. The auto-transplantation arm includes the transplanting claw, convex gear and removing gear-gap parts. It transfers the whirling operation of planet gear into straight-line operation of pick-up seedling. The manual finger scratching and planting were simulated by two pins at the end of the seedling arm. The auto-transplantation mechanism combines the pick-up and planting. The transplanting trajectory and the location of pick-up and planting were special. Thus, it is essential to design new mechanism accordance with the movement of pick-up clip and achieve “Double beak sharp” trajectory. In this paper, we designed a device of bouncing clip to lengthen the trajectory to realize the function of pick-up and planting, and it could facilitate the integration of the planting. At the same time, when the claw moves nearly to the pot seedling, the seedling needle was inserted into the soil with a certain angle of inclination, which could effectively avoid the injury of the seedlings and the interference with the seedling box. Based on the kinematics characteristics of the mechanism, a corresponding mathematic model was established, and the Visual Basic 6.0 software was used to optimize the mechanism parameters. The program was used to analyze the influence of the parameters of mechanism on the trajectory and attitude of the “Double beak sharp". Finally, the best group of mechanism parameters was selected, and then the 3D design and components assembly were carried out based on SolidWorks 2015 software. Importing the 3D model to Adams, the trajectories of seedling needle could be obtained by the kinematics simulation. Finally, the prototype test was carried out and the test trajectory of the prototype was obtained by the test platform. Through the platform, the operation process was recorded by high-speed camera. Therefore, the trajectories of seedling needle could be tracked through the Bestcam picture analysis software. The results were basically the same among the simulation trajectory, the test trajectory of the prototype and the theoretical trajectory, which verified the correctness and feasibility of the design in this paper. Experimental research was carried out using the prototype, “Marigold chrysanthemum” seedlings were selected in the experiment, the basic composition of the pot seedling combines the pearl cave and peat mud, with the water component of 46%, the seedling tray were eight lines and 16 rows, both the length and width of seedling were 31 mm, and depth was 43 mm, and the test seedlings of marigold were 35 days, with the average height of 10 cm. The rotation speed of the mechanism was set as 35 r/min, its mean efficiency was 70 stems per minute. The obtained seedling success rate was 97.27%, while the transplanting success rate was 77.62%. It reflected the practicality of the integrated transplanting mechanism; the research could provide a reference for the key technology of automatic transplanting. [ABSTRACT FROM AUTHOR]

Tractor transmission shaft is one of the components that affect the reliability of the tractor. Compiling load spectrum which can reflect the actual working conditions of high-power tractor drive shaft is of great significance to improve the reliability of the tractor. It is time consuming and expensive to obtain the actual measurement for load spectrum of the whole life cycle, so extrapolated methods are always applied by using the load spectrum of the limited measurement duration. However, the traditional method of rain flow counting and rain basin extrapolation in the process of compiling load spectrum of transmission system has limitations, this paper proposed a POT (peak over threshold) model based time domain extrapolation method for driving shaft load of high-power tractor. Firstly, a set of wireless torque measurement system for tractor transmission shaft is built, which mainly includes strain gauges, batteries, wireless strain nodes and wireless acquisition terminals. The strain gauge is pasted on the proper part of the tractor drive shaft and connected with the wireless torque node. The wireless transmitter is encapsulated in the wireless torque node and transmits the measured torque signal to the wireless receiver synchronously. The test data of the drive shaft under field working conditions are stored in a portable computer connected to a wireless receiver. Then, POT model is established based on extremum theory to extract the peak and valley values of the test data and eliminate the small load cycles, and the intervals of the optimal thresholds are determined by using the mean excess function graph, which are [492, 501] N·m for the upper limit and [325, 334] N·m for the lower limit, respectively. Thirdly, the data in the threshold interval is divided according to a certain gradient, and the fitting effect corresponding to each threshold is preliminarily tested by calculating R-square. The grey relational degree analysis method is used to select the optimal threshold and calculate the grey relational degree of each threshold in the corresponding threshold range. the optimum threshold values 497 N·m for upper limit and 333 N·m for lower limit are achieved by comparing the values of grey correlation degree corresponding to different threshold. The excess threshold data are fitted by generalized Pareto distribution and the CDF and P-P figures are plotted to evaluate the effectiveness of fitting test. The results show that the fitting curve of generalized distribution function can accurately describe the distribution law of extreme samples. Finally, according to the fitted generalized distribution function, the load sequence with the same distribution is generated. The time domain extrapolation of the load is achieved by replacing the original extremum load with the generated sequence. The cumulative frequency curve of the load cycle is developed according to the original load data and the results obtained by the time domain extrapolation method and the rain flow extrapolation method. The results show that the frequency curves obtained by the traditional rain flow extrapolation method and the time domain extrapolation method are consistent. Compared to the original load data, both load extrapolation results have a small amount of large extreme load which did not occur during the test. Therefore, it can be indicated that the load extrapolation method based on the POT model not only increases the frequency of the load cycle, but also extrapolates the load extreme value to a certain extent based on the distribution law of the large extreme load. The accuracy of the time domain extrapolation method is verified. The load time domain extrapolation method developed in this paper has good applicability to the measured loads of high-power tractor transmission shaft in operation conditions. Compared with the rain basin extrapolation method, the load time domain extrapolation method based on POT model can not only obtain the load time domain sequence of arbitrary mileage, but also retain the order of the measured load cycle to a great extent, which can provide reliable data support for the indoor load spectrum loading test of high-power tractor transmission system in the future. [ABSTRACT FROM AUTHOR]

Cotton stalk is an important renewable resource. China is rich in cotton stalk, if such a large amount of resources are recycled, it will produce huge economic benefits. But most of them are not recycled at present. In order to improve the mechanized recovery level of cotton stalk, study the influence of different parameters on the mechanized recovery of cotton stalk, and solve the outstanding problems such as high cotton stalk plucking rate and high cotton stalk leakage rate, this paper studied and designed a toothed disc cotton stalk harvester. The machine was consisted of suspension device, limit wheel, pull-out tooth plate, stalk discharge device, hydraulic motor, hydraulic pipeline and hydraulic control box. The key component of the machine was a toothed disc type stalk pulling device. During operation, the cotton stalk was lifted out through the toothed disc, and then the cotton stalk was discharged to the surface through the stalk discharge device. Leakage rate and plucking rate of cotton stalk were the main parameters to evaluate the performance of toothed disc cotton stalk harvester. In this paper, Box-benhnken central combination test method was used to study the working parameters of toothed disc cotton stalk harvester. Three-factor and three-level quadratic regression orthogonal test was designed. The three-dimensional model of response surface was established with the diameter of the toothed disc, the toothed disc speed ratio and the lifting height as the influencing factors. The influence of each factor on the quality of work was analyzed, and the influencing factors were optimized synthetically. The results showed that the lifting height and the toothed disc speed ratio had significant effects on the cotton stalk plucking rate (P< 0.01), while the lifting height, the diameter of the toothed disc and the toothed disc speed ratio had significant effects on the rate of cotton stalk leakage rate (P<0.01). The working parameters of the machine were deduced from the regression model optimization as follows: the lifting height was 66.2 mm, the diameter of the toothed disc was 627.59 mm, and the toothed disc speed ratio was 0.57. In November 2018, field test was carried out in the Yellow River Delta (Binzhou) National Agricultural Science and Technology Park. Test area was divided into 17 test plots, leakage rate and plucking rate of cotton stalk at each test plot were calculated. The results of the Daejeon experiment showed that when the lifting height was 70 mm, diameter of the toothed disc was 630 mm and the toothed disc speed ratio was 0.57, the cotton stalk plucking rate could reach 1.5% and the cotton stalk leakage rate was low to 3.0%. The test results showed that the theoretical results were coincident with the measuring results, and the error between them was less than 4%. The research results can provide references for the structure improvement design and operation parameters optimization of toothed disc cotton stalk harvester. [ABSTRACT FROM AUTHOR]

Tractor transmission shaft is one of the components that affect the reliability of the tractor. Compiling load spectrum which can reflect the actual working conditions of high-power tractor drive shaft is of great significance to improve the reliability of the tractor. It is time consuming and expensive to obtain the actual measurement for load spectrum of the whole life cycle, so extrapolated methods are always applied by using the load spectrum of the limited measurement duration. However, the traditional method of rain flow counting and rain basin extrapolation in the process of compiling load spectrum of transmission system has limitations, this paper proposed a POT (peak over threshold) model based time domain extrapolation method for driving shaft load of high-power tractor. Firstly, a set of wireless torque measurement system for tractor transmission shaft is built, which mainly includes strain gauges, batteries, wireless strain nodes and wireless acquisition terminals. The strain gauge is pasted on the proper part of the tractor drive shaft and connected with the wireless torque node. The wireless transmitter is encapsulated in the wireless torque node and transmits the measured torque signal to the wireless receiver synchronously. The test data of the drive shaft under field working conditions are stored in a portable computer connected to a wireless receiver. Then, POT model is established based on extremum theory to extract the peak and valley values of the test data and eliminate the small load cycles, and the intervals of the optimal thresholds are determined by using the mean excess function graph, which are [492, 501] N·m for the upper limit and [325, 334] N·m for the lower limit, respectively. Thirdly, the data in the threshold interval is divided according to a certain gradient, and the fitting effect corresponding to each threshold is preliminarily tested by calculating R-square. The grey relational degree analysis method is used to select the optimal threshold and calculate the grey relational degree of each threshold in the corresponding threshold range. the optimum threshold values 497 N·m for upper limit and 333 N·m for lower limit are achieved by comparing the values of grey correlation degree corresponding to different threshold. The excess threshold data are fitted by generalized Pareto distribution and the CDF and P-P figures are plotted to evaluate the effectiveness of fitting test. The results show that the fitting curve of generalized distribution function can accurately describe the distribution law of extreme samples. Finally, according to the fitted generalized distribution function, the load sequence with the same distribution is generated. The time domain extrapolation of the load is achieved by replacing the original extremum load with the generated sequence. The cumulative frequency curve of the load cycle is developed according to the original load data and the results obtained by the time domain extrapolation method and the rain flow extrapolation method. The results show that the frequency curves obtained by the traditional rain flow extrapolation method and the time domain extrapolation method are consistent. Compared to the original load data, both load extrapolation results have a small amount of large extreme load which did not occur during the test. Therefore, it can be indicated that the load extrapolation method based on the POT model not only increases the frequency of the load cycle, but also extrapolates the load extreme value to a certain extent based on the distribution law of the large extreme load. The accuracy of the time domain extrapolation method is verified. The load time domain extrapolation method developed in this paper has good applicability to the measured loads of high-power tractor transmission shaft in operation conditions. Compared with the rain basin extrapolation method, the load time domain extrapolation method based on POT model can not only obtain the load time domain sequence of arbitrary mileage, but also retain the order of the measured load cycle to a great extent, which can provide reliable data support for the indoor load spectrum loading test of high-power tractor transmission system in the future. [ABSTRACT FROM AUTHOR]

Cotton stalk is an important renewable resource. China is rich in cotton stalk, if such a large amount of resources are recycled, it will produce huge economic benefits. But most of them are not recycled at present. In order to improve the mechanized recovery level of cotton stalk, study the influence of different parameters on the mechanized recovery of cotton stalk, and solve the outstanding problems such as high cotton stalk plucking rate and high cotton stalk leakage rate, this paper studied and designed a toothed disc cotton stalk harvester. The machine was consisted of suspension device, limit wheel, pull-out tooth plate, stalk discharge device, hydraulic motor, hydraulic pipeline and hydraulic control box. The key component of the machine was a toothed disc type stalk pulling device. During operation, the cotton stalk was lifted out through the toothed disc, and then the cotton stalk was discharged to the surface through the stalk discharge device. Leakage rate and plucking rate of cotton stalk were the main parameters to evaluate the performance of toothed disc cotton stalk harvester. In this paper, Box-benhnken central combination test method was used to study the working parameters of toothed disc cotton stalk harvester. Three-factor and three-level quadratic regression orthogonal test was designed. The three-dimensional model of response surface was established with the diameter of the toothed disc, the toothed disc speed ratio and the lifting height as the influencing factors. The influence of each factor on the quality of work was analyzed, and the influencing factors were optimized synthetically. The results showed that the lifting height and the toothed disc speed ratio had significant effects on the cotton stalk plucking rate (P< 0.01), while the lifting height, the diameter of the toothed disc and the toothed disc speed ratio had significant effects on the rate of cotton stalk leakage rate (P<0.01). The working parameters of the machine were deduced from the regression model optimization as follows: the lifting height was 66.2 mm, the diameter of the toothed disc was 627.59 mm, and the toothed disc speed ratio was 0.57. In November 2018, field test was carried out in the Yellow River Delta (Binzhou) National Agricultural Science and Technology Park. Test area was divided into 17 test plots (each plots is 30 m×0.76 m), leakage rate and plucking rate of cotton stalk at each test plot were calculated. The results of the Daejeon experiment showed that when the lifting height was 70 mm, diameter of the toothed disc was 630 mm and the toothed disc speed ratio was 0.57, the cotton stalk plucking rate could reach 1.5% and the cotton stalk leakage rate was low to 3.0%. The test results showed that the theoretical results were coincident with the measuring results, and the error between them was less than 4%. The research results can provide references for the structure improvement design and operation parameters optimization of toothed disc cotton stalk harvester. [ABSTRACT FROM AUTHOR]

Deep rotary tillage is a hot and difficult problem in the research field of tillage machinery. Scholars at home and abroad have made a lot of explorations on deep rotary tillage technology and theory. At present, deep rotary tillage is mainly realized through the following three methods: 1) plowing depth was increased by directly increasing the diameter of the knife roller; 2)Two-axis stratified rotary tillage. Two rows of knife rollers are set in front and back for the first rotary tillage of the former one, and then the latter one for further rotary tillage; 3) subsoil reverse rotary tillage, that is, deep tillage is achieved by sinking the knife shaft below the surface. These three methods can achieve the goal of deep rotation tillage, but they all have their own disadvantages. Considering the characteristics of oblique rotary tilling and reverse tilling, the principle of oblique submerged reverse rotary tillage is put forward in this paper, which can not only destroy the soil by “pull” but also reduce the heaping soil as well as make the central transmission box easy to sink subsoil, and realize low energy consumption deep tilling with short knife. The back-up amount of tilting rotary tilter directly depends on the performance of tilting rotary tilter. Oblique submerged reverse rotary tillage is put forward in this paper. It is important to study the mechanism of throwing soil to optimize the design of this machine. Oblique submerged reverse rotary tillage is a new type of rotary tillage. It is important to study the mechanism of throwing soil to optimize the design of inclined subterranean reversal rotary tiller. In this paper, a simulation model of SPH (Smoothed Particle Hydrodynamics) is established on the LS-DYNA platform. The model is used to reverse the rotary tillage in different working conditions. The simulation results show that the post-soil rate of different layers in the reverse rotation of different parameters under different parameters is obtained. The post-soil rate of different layers obtained under the same conditions and the post-casting of different layers obtained by the indoor soil trough test are obtained. The soil rate was compared and analyzed. The verification results show that the maximum simulation error is 12.50%, the minimum simulation error is 0.20%, and the average error is 3.09%. Applying the corrected simulation model, the oblique angle, the forward speed, the depth of the submerged soil and the speed of the cutter roll were taken as the four factors of the test, and three levels were taken for each factor. Afterwards, the throwing rate was measured and the tilt was set. The virtual orthogonal experiment of reversing the rotary tillage and throwing soil was conducted. The test results were analyzed by the range analysis method, the variance analysis method and the regression analysis method. The data analysis results show that the primary and secondary order of the impact rate after the impact is the subsoil depth and the oblique angle, the forward speed and the knife roll speed. The influence on the post-lost rate is not significant, and the mathematical relationship model of the subsoil depth, the oblique angle and the post-lost rate is obtained. According to the results of virtual experiment, the physical prototype of the inclined submersible soil reverse rotation tillage machine was optimized and the field experiment was carried out. The field test results showed that the reverse rotation of the inclined subterranean soil successfully solved the problem of the rotary tiller bracket and the central transmission box. And with the R175 standard rotary cultivator, the tilling depth of 20 cm was achieved, and deep tilling using short knife was realized in this paper. [ABSTRACT FROM AUTHOR]

Grain cleaning is the core technology of peanut harvest. Therefore, in the process of peanut harvesting, how to enhance operation fluency and efficiency, and to ensure technical indicators such as low loss rate of cleaning, low impurity rate of peanut pods, has been a difficult technical problem of whole-feed peanut combine harvester. In order to settle the above difficulties, a cleaning device of tangential flow and whole-feed peanut combine harvester was designed, realizing the grain winnowed combined with screened, one-time large and small sundries clearance, sieve surface unencumbered. The cleaning device of tangential flow and whole-feed peanut combine harvester consisted of pole sieve, multi-stage elastic sieve, behind sieve, straw-shaking wheel, eccentric sleeve, main fan, auxiliary fan. The vibrating sieve consisted of pole sieve, multi-stage elastic sieve, behind sieve. Pole sieve was above the vibrating sieve. Multi-stage elastic sieve and behind sieve were below the vibrating sieve. Combined with existed mechanism advantages, a crank-rocker mechanism which consisted of the vibrating sieve and swinging arm was brought forward. In the application of cleaning device of tangential flow and whole-feed peanut combine harvester, there are many problems such as high impurity rate of peanut pods, high loss rate of cleaning, agricultural film tangles, and debris blockage. Utilizing kineto-statics method, in this paper, we researched relative motion of grain on the sieve surface, analyzed limiting conditions of grain upglide, downglide, jump from sieve surface, and determined the key motion parameter in theory. Vibration acceleration of vibrating sieve was 17.5-24.5 m/s2. Amplitude of vibrating sieve was 7.5-17.5 mm. Vibration frequency of vibrating sieve was 5-9 Hz. Utilizing D'Alembert's principle, in this paper, we also researched sieve force under alternating loads, determined the important structure parameter of sieve. Cleaning device was matched onto the whole-feed combine and a lot of tests were carried out in the field. Loss rate of cleaning and impurity rate of peanut pods were taken as the evaluation indicator of cleaning quality. The key factors affecting cleaning quality were researched by field experiment in this paper. A scheme of orthogonal test, which included 3 factors and 3 levels, was designed. That key factor included amplitude, vibration frequency and revolving speed of main fan. The value range of amplitude and vibration frequency was based on the preceding theoretical analysis. The value range of revolving speed of main fan was based on single factor experiment. The experimental results showed that significant order for multi-factors affected on cleaning quality was: revolving speed of main fan, amplitude, vibration frequency. Within the scope of the 95% confidence coefficient, revolving speed of main fan was extremely significant for cleaning quality, amplitude and vibration frequency were significant for cleaning quality. The optimal parameter combination was that revolving speed of main fan was 2 100 r/min, amplitude was 12.5 mm, vibration frequency was 9 Hz. Under the above optimal parameters, field experiments were carried out, loss rate of cleaning was 5.03% and impurity rate of peanut pods was 5.39%. The operation of cleaning device is fluent, almost no agricultural film tangles and debris blockage. The research results provide theoretical basis for design and parameter optimization of whole-feed peanut combine harvester and cleaning device [ABSTRACT FROM AUTHOR]

Grain loss rate is one of the most important performance index of corn head in mechanized harvesting. Seed harvesting is the main development direction of mechanized corn harvesting. The characters of seed harvesting corn variaty increased the urgency to reduce grain loss on corn head. The paper was proposed to solve the problem of grain loss on corn head. Theoretical analysis was conducted to the snapping process. Corn ear was subjected to pull force by the snapping rolls and the pull force transferred by corn stalk. Corn kernels were divided into 2 types due to their force condition. A kernel at the bottom end of corn ear was subjected to reaction forces by stripper plates, corn cob and the adjacent kernels and shear force by the pedicel. Kernels out of contact with the stripper plates were subjected to reaction forces by the adjacent kernels, pull force and shear force by corn cob. As the impact force was related to the impact time according to the theorem of impulse, the paper analyzed collision model between corn ear and stripper plates in the snapping process. A mathematical model was obtained about the impact time and intrinsic parameters of the system. The impact time was dependent on system mass, stiffness coefficient and damping coefficient, which lays on the mechanical structure and materials of collision objects. So, the impact force would decrease as the impact time could be prolonged by reducing the stiffness coefficient and raising the damping coefficient. The quantity of shed kernels could be reduced consequently. The paper proposed a corn head with wheel type rigid-flexible coupling snapping device to reduce loss. The corn head consisted of the frame, gear-box, snapping rolls, gathering chain, wheel type rigid-flexible coupling snapping device, and chain wheels. The wheel type rigid-flexible coupling snapping device consisted of snapping wheel axle, spring seat axle, supporting axle, buffer spring, and snapping wheel frame. Force analysis was conducted on the snapping wheel. According to the force conditions and dimension boundary condition, the structure diameters of snapping wheel, snapping wheel frame, and buffer spring were confirmed. In order to obtain the optimal parameters with the minimum loss rate of wheel type rigid-flexible coupling snapping device, the optimization experiments were conducted of the factors at 3 different levels. In the optimization experiments, the snapping wheel radius was designed at 10, 15 and 20 mm respectively, the flexible body thickness was at 2, 4 and 6 mm respectively, the snapping rolls rotating speed at 700, 800 and 900 r/min respectively. The Response Surface Analysis method was used to design the experiments. The software Design-Expert 8.0.6.1 was used to analyze the data. Regression equation was induced according to the experiment and analysis above. The optimal combination of wheel type coupling snapping device was as follows: The snapping rolls rotating speed was 700 r/min, the snapping wheel radius was 15 mm, the flexible body thickness was 4 mm. Verification contrast test was conducted between corn head with wheel type rigid-flexible coupling snapping device and the one with snapping rolls and stripper plates on corns at different moisture contents. As the kernels moisture contents were 21.8%, 16.7% and 13.4%, the grain loss rate decreased 53.4%, 48.6% and 47.0% respectively. This study provides not only theoretical basis but also design reference for the improvement of corn harvester design. [ABSTRACT FROM AUTHOR]

In order to improve the processing quality and reliability of the cleaning screen of grain combine harvester, it is necessary to eliminate the manufacturing defects in the design and pilot stage, which causing the additional load, , and to locate and eliminate the processing defects by measuring in the production stage. In this paper, a method can locate and calculate the exciting forces act on the connection points of cleaning screen and thresher body by classical transfer path analysis (TPA ) were developed. By measuring and comparing the vibrations of the connection points, it is found that the vibration frequency components were the same and were strongly correlated, so it is impossible to find the main excitation source by analyzing the frequency to locate the manufacturing defects. According to the relationship between exciting force and defect, it is pointed out that there should be major manufacturing defects near the maximum excitation force. The vibration of connection points and a certain observation point of the test bench were measured by using triaxial accelerometers and dynamic signal analyzer , and the characteristics of time domain and time-frequency domain were analyzed. The results showed that although there was no change in the frequency components in the spectrum, the amplitude changed greatly, and the phase changed greatly at different times of each frequencies. The transfer functions of the connection points to each measurement points were detected by using a modal force hammer and vibration measuring devices. Since the phase was unstable, according to the principle that the product of each excitation force and the transfer function (ie, the contribution of the excitation force to the vibration) had the largest vibration response in the same direction, the maximum acceleration amplitude was introduced into the inverse matrix method formula, and the influence of the phase was ignored, and the problem that the ill-conditioned matrix of the transfer function matrix could not be inverted was solved by increasing the measurement point, the generalized inverse matrix of transfer function was calculated by singular value decomposition. The calculated excitation force was optimized by least squares method, and finally the practical incentive calculation formula was derived. In order to verify the validity of the method, the magnitude of the excitation force during normal operation and the contribution to the vibration in Ydirection of the observation point were calculated. The results showed that the sum of contributions was only slightly smaller than the measured acceleration, which was about 84.7%-94.6% of the measured value, the excitation force calculated by this method was basically correct. The keyway clearance was used as a typical defect for the location verification test. It was found that the amplitude of each frequency in the excitation force spectrum near the defect increased significantly (71%-3 271%), while the amplitude of the slot excitation force away from the defect was only slightly added, the effectiveness of the positioning method was verified. The defect localization method proposed in this paper only adds one accelerometer and one measuring instrument to the original cleaning screening assembly quality inspection platform, the vibration excitation force at the connection points between the cleaning screen and the rack mounting could also be roughly calculated by measuring 4-8 acceleration responses. [ABSTRACT FROM AUTHOR]

Agricultural machine automatic navigation is one of the key technologies in precision agriculture technology system, the in-depth study is important in scientific research, application and social values. In this paper, we investigated the navigation problems in the application of the farm work, including slow on-line speed, bad on-line stability, and poor adaptability of bumpy complex road surface. These problems can be summarized as the speed and stability problems of track tracking in the case of large position deviation or large course deviation. Through the analysis of the work principle and control parameters function of the navigation, a conclusion is made that the correct speed and stability of the position deviation and course deviation of agricultural machinery can be improved by allocating the weight of the position deviation wheel angle decision quantity and course deviation wheel angle decision quantity reasonably. Then in this paper, we developed the navigation control algorithm based on the agricultural machine kinematics model and the pole optimal configuration theory. Because of the small angle linearization of course deviation angle and wheel angle during the deducing, the control law can achieve good control effect only in the ideal straight path tracking control with small position deviation, course deviation, and wheel angle. Based on this, a path tracking control method of aiming pursuit model for agricultural machine navigation was proposed aiming at improving the on-line speed, stability and adaptability to complex road surface of the automatic navigation system of agricultural machine. In this method, we selected a tracking target point on the planning path of agricultural machine ahead, and tracked the target point by controlling the steering wheel angle. The direction of the agricultural machine vehicle center point to the target point was called as the aiming course. The desired steering angle would be larger when the deviation was larger between the course of agricultural machine and the aiming course, with a rapid correction of aiming course deviation to achieve the goal of fast tracking the target path. On the other hand, the desired steering angle would be smaller when the deviation was smaller between the course of agricultural machine and the aiming course, with a stable tracking to aiming path to achieve the goal of stable tracking the target path. In this model, the steering wheel angle was designed to be K times of the aiming course deviation and K was called as control gain. The length of the projection of the agricultural machine vehicle center to the target point vector on the planning path was named as the preview distance. The control gain and the preview distance were two important parameters that affected the control effect of the model. In this paper, there were three steps to prove the feasibility of the method. The control gain K and the preview distance were set up by referring to the result of the pole optimal configuration method based on the kinematic model of agricultural machine. By comparing two methods formula, the position deviation wheel angle decision quantity had a linear relationship with the position deviation in the kinematics model method and the position deviation wheel angle decision quantity had an inverse tangent function relationship with the position deviation. The inverse tangent function relation was more beneficial to maintain proper weight of position deviation wheel angle decision quantity and course deviation wheel angle decision quantity that would make the path tracking control of agricultural machinery navigation more rapid and stable. Simulation analysis results of aiming pursuit model algorithm in different position and different course deviation showed that the proposed method had a fast and stable path tracking performance and good robustness and adaptability to the navigation path tracking. The test results of agricultural machine showed that the control method proposed in this paper had a good effect in the rapid responsibility and line tracking performance. In the case of 0.5, 1, 1.5 m initial position error, the on-line time was 6.8, 8.2, 9.4 s, respectively, the corresponding travelling distance was 6.73, 8.11 and 9.33 m, respectively and the corresponding overshoot was 5.2, 7.0, 8.5 cm, respectively. The maximum error of straight-line path tracking for bumpy uneven field was not more than 4.23 cm, the mean value of the absolute value of the error was 1 cm, and the standard deviation was 1.25 cm, which satisfied the operation requirements of agricultural machine. [ABSTRACT FROM AUTHOR]

In order to develop a more efficient and universal flower auto-transplantation technique, an auto-transplantation mechanism with the integrated function of seedling pick-up and transplanting has been designed. This mechanism involves gear driving and two transplanting arms of the same structure. The gear driving system is made up of one semi-circle gear, four oval planet gears and concave-convex lock-up arc. It aims to move with the non uniform speed through the operation of planet gears and pulling and imbedding of concave-convex lock-up arc. The auto-transplantation arm includes the transplanting claw, convex gear and removing gear-gap parts. It transfers the whirling operation of planet gear into straight-line operation of pick-up seedling. The manual finger scratching and planting were simulated by two pins at the end of the seedling arm. The auto-transplantation mechanism combines the pick-up and planting. The transplanting trajectory and the location of pick-up and planting were special. Thus, it is essential to design new mechanism accordance with the movement of pick-up clip and achieve “Double beak sharp” trajectory. In this paper, we designed a device of bouncing clip to lengthen the trajectory to realize the function of pick-up and planting, and it could facilitate the integration of the planting. At the same time, when the claw moves nearly to the pot seedling, the seedling needle was inserted into the soil with a certain angle of inclination, which could effectively avoid the injury of the seedlings and the interference with the seedling box. Based on the kinematics characteristics of the mechanism, a corresponding mathematic model was established, and the Visual Basic 6.0 software was used to optimize the mechanism parameters. The program was used to analyze the influence of the parameters of mechanism on the trajectory and attitude of the “Double beak sharp". Finally, the best group of mechanism parameters was selected, and then the 3D design and components assembly were carried out based on SolidWorks 2015 software. Importing the 3D model to Adams, the trajectories of seedling needle could be obtained by the kinematics simulation. Finally, the prototype test was carried out and the test trajectory of the prototype was obtained by the test platform. Through the platform, the operation process was recorded by high-speed camera. Therefore, the trajectories of seedling needle could be tracked through the Bestcam picture analysis software. The results were basically the same among the simulation trajectory, the test trajectory of the prototype and the theoretical trajectory, which verified the correctness and feasibility of the design in this paper. Experimental research was carried out using the prototype, “Marigold chrysanthemum” seedlings were selected in the experiment, the basic composition of the pot seedling combines the pearl cave and peat mud, with the water component of 46%, the seedling tray were eight lines and 16 rows, both the length and width of seedling were 31 mm, and depth was 43 mm, and the test seedlings of marigold were 35 days, with the average height of 10 cm. The rotation speed of the mechanism was set as 35 r/min, its mean efficiency was 70 stems per minute. The obtained seedling success rate was 97.27%, while the transplanting success rate was 77.62%. It reflected the practicality of the integrated transplanting mechanism; the research could provide a reference for the key technology of automatic transplanting. [ABSTRACT FROM AUTHOR]

In order to develop a more efficient and universal flower auto-transplantation technique, an auto-transplantation mechanism with the integrated function of seedling pick-up and transplanting has been designed. This mechanism involves gear driving and two transplanting arms of the same structure. The gear driving system is made up of one semi-circle gear, four oval planet gears and concave-convex lock-up arc. It aims to move with the non uniform speed through the operation of planet gears and pulling and imbedding of concave-convex lock-up arc. The auto-transplantation arm includes the transplanting claw, convex gear and removing gear-gap parts. It transfers the whirling operation of planet gear into straight-line operation of pick-up seedling. The manual finger scratching and planting were simulated by two pins at the end of the seedling arm. The auto-transplantation mechanism combines the pick-up and planting. The transplanting trajectory and the location of pick-up and planting were special. Thus, it is essential to design new mechanism accordance with the movement of pick-up clip and achieve “Double beak sharp” trajectory. In this paper, we designed a device of bouncing clip to lengthen the trajectory to realize the function of pick-up and planting, and it could facilitate the integration of the planting. At the same time, when the claw moves nearly to the pot seedling, the seedling needle was inserted into the soil with a certain angle of inclination, which could effectively avoid the injury of the seedlings and the interference with the seedling box. Based on the kinematics characteristics of the mechanism, a corresponding mathematic model was established, and the Visual Basic 6.0 software was used to optimize the mechanism parameters. The program was used to analyze the influence of the parameters of mechanism on the trajectory and attitude of the “Double beak sharp". Finally, the best group of mechanism parameters was selected, and then the 3D design and components assembly were carried out based on SolidWorks 2015 software. Importing the 3D model to Adams, the trajectories of seedling needle could be obtained by the kinematics simulation. Finally, the prototype test was carried out and the test trajectory of the prototype was obtained by the test platform. Through the platform, the operation process was recorded by high-speed camera. Therefore, the trajectories of seedling needle could be tracked through the Bestcam picture analysis software. The results were basically the same among the simulation trajectory, the test trajectory of the prototype and the theoretical trajectory, which verified the correctness and feasibility of the design in this paper. Experimental research was carried out using the prototype, “Marigold chrysanthemum” seedlings were selected in the experiment, the basic composition of the pot seedling combines the pearl cave and peat mud, with the water component of 46%, the seedling tray were eight lines and 16 rows, both the length and width of seedling were 31 mm, and depth was 43 mm, and the test seedlings of marigold were 35 days, with the average height of 10 cm. The rotation speed of the mechanism was set as 35 r/min, its mean efficiency was 70 stems per minute. The obtained seedling success rate was 97.27%, while the transplanting success rate was 77.62%. It reflected the practicality of the integrated transplanting mechanism; the research could provide a reference for the key technology of automatic transplanting. [ABSTRACT FROM AUTHOR]

In order to develop a more efficient and universal flower auto-transplantation technique, an auto-transplantation mechanism with the integrated function of seedling pick-up and transplanting has been designed. This mechanism involves gear driving and two transplanting arms of the same structure. The gear driving system is made up of one semi-circle gear, four oval planet gears and concave-convex lock-up arc. It aims to move with the non uniform speed through the operation of planet gears and pulling and imbedding of concave-convex lock-up arc. The auto-transplantation arm includes the transplanting claw, convex gear and removing gear-gap parts. It transfers the whirling operation of planet gear into straight-line operation of pick-up seedling. The manual finger scratching and planting were simulated by two pins at the end of the seedling arm. The auto-transplantation mechanism combines the pick-up and planting. The transplanting trajectory and the location of pick-up and planting were special. Thus, it is essential to design new mechanism accordance with the movement of pick-up clip and achieve “Double beak sharp” trajectory. In this paper, we designed a device of bouncing clip to lengthen the trajectory to realize the function of pick-up and planting, and it could facilitate the integration of the planting. At the same time, when the claw moves nearly to the pot seedling, the seedling needle was inserted into the soil with a certain angle of inclination, which could effectively avoid the injury of the seedlings and the interference with the seedling box. Based on the kinematics characteristics of the mechanism, a corresponding mathematic model was established, and the Visual Basic 6.0 software was used to optimize the mechanism parameters. The program was used to analyze the influence of the parameters of mechanism on the trajectory and attitude of the “Double beak sharp". Finally, the best group of mechanism parameters was selected, and then the 3D design and components assembly were carried out based on SolidWorks 2015 software. Importing the 3D model to Adams, the trajectories of seedling needle could be obtained by the kinematics simulation. Finally, the prototype test was carried out and the test trajectory of the prototype was obtained by the test platform. Through the platform, the operation process was recorded by high-speed camera. Therefore, the trajectories of seedling needle could be tracked through the Bestcam picture analysis software. The results were basically the same among the simulation trajectory, the test trajectory of the prototype and the theoretical trajectory, which verified the correctness and feasibility of the design in this paper. Experimental research was carried out using the prototype, “Marigold chrysanthemum” seedlings were selected in the experiment, the basic composition of the pot seedling combines the pearl cave and peat mud, with the water component of 46%, the seedling tray were eight lines and 16 rows, both the length and width of seedling were 31 mm, and depth was 43 mm, and the test seedlings of marigold were 35 days, with the average height of 10 cm. The rotation speed of the mechanism was set as 35 r/min, its mean efficiency was 70 stems per minute. The obtained seedling success rate was 97.27%, while the transplanting success rate was 77.62%. It reflected the practicality of the integrated transplanting mechanism; the research could provide a reference for the key technology of automatic transplanting. [ABSTRACT FROM AUTHOR]

In order to develop a more efficient and universal flower auto-transplantation technique, an auto-transplantation mechanism with the integrated function of seedling pick-up and transplanting has been designed. This mechanism involves gear driving and two transplanting arms of the same structure. The gear driving system is made up of one semi-circle gear, four oval planet gears and concave-convex lock-up arc. It aims to move with the non uniform speed through the operation of planet gears and pulling and imbedding of concave-convex lock-up arc. The auto-transplantation arm includes the transplanting claw, convex gear and removing gear-gap parts. It transfers the whirling operation of planet gear into straight-line operation of pick-up seedling. The manual finger scratching and planting were simulated by two pins at the end of the seedling arm. The auto-transplantation mechanism combines the pick-up and planting. The transplanting trajectory and the location of pick-up and planting were special. Thus, it is essential to design new mechanism accordance with the movement of pick-up clip and achieve “Double beak sharp” trajectory. In this paper, we designed a device of bouncing clip to lengthen the trajectory to realize the function of pick-up and planting, and it could facilitate the integration of the planting. At the same time, when the claw moves nearly to the pot seedling, the seedling needle was inserted into the soil with a certain angle of inclination, which could effectively avoid the injury of the seedlings and the interference with the seedling box. Based on the kinematics characteristics of the mechanism, a corresponding mathematic model was established, and the Visual Basic 6.0 software was used to optimize the mechanism parameters. The program was used to analyze the influence of the parameters of mechanism on the trajectory and attitude of the “Double beak sharp". Finally, the best group of mechanism parameters was selected, and then the 3D design and components assembly were carried out based on SolidWorks 2015 software. Importing the 3D model to Adams, the trajectories of seedling needle could be obtained by the kinematics simulation. Finally, the prototype test was carried out and the test trajectory of the prototype was obtained by the test platform. Through the platform, the operation process was recorded by high-speed camera. Therefore, the trajectories of seedling needle could be tracked through the Bestcam picture analysis software. The results were basically the same among the simulation trajectory, the test trajectory of the prototype and the theoretical trajectory, which verified the correctness and feasibility of the design in this paper. Experimental research was carried out using the prototype, “Marigold chrysanthemum” seedlings were selected in the experiment, the basic composition of the pot seedling combines the pearl cave and peat mud, with the water component of 46%, the seedling tray were eight lines and 16 rows, both the length and width of seedling were 31 mm, and depth was 43 mm, and the test seedlings of marigold were 35 days, with the average height of 10 cm. The rotation speed of the mechanism was set as 35 r/min, its mean efficiency was 70 stems per minute. The obtained seedling success rate was 97.27%, while the transplanting success rate was 77.62%. It reflected the practicality of the integrated transplanting mechanism; the research could provide a reference for the key technology of automatic transplanting. [ABSTRACT FROM AUTHOR]

Castor is one of the top ten oil crops in the world, which has a extremely high economic value. For a long time, the harvesting of castor bean has relied on manual operations, so the development of the castor industry have been greatly restricted by the high labor intensity and low efficiency. At present, there are few studies on harvesting machinery of castor, and the mechanization of castor harvesting is still in the initial stage. The existing castor harvesting equipments are not suitable for the growth features of castor, which has the problems of high loss rate and high damage rate. In order to solve these problems, a brush-roller harvesting method was proposed in this paper. The harvesting principle of brush-roller castor harvester is that the castor capsules are separated from the plant by the brushing force caused from the brush wire. According to the physical characteristics and planting mode of castor, the picking mechanism of brush-roller castor harvester was designed. Firstly, the structure of the picking mechanism was introduced, the picking mechanism is mainly composed of crop divider, brush roller, screw conveyor, transfer case, et. Then, the kinematic and mechanical analysis of the working process of the mechanism was carried out, so as to determine the structural parameters and working parameters of each part of the picking mechanism. In order to improve the harvesting quality of castor, we conducted a field experiment in October 2020 in Hohhot, Inner Mongolia. In the field experiment, Box-benhnken response surface design theory was used on the basis of single fator experiment to optimize the working parameters of the picking mechanism. The picking rate, the breakage rate and the impurity rate were used as the evaluation indexes of working quality. And the moving speed, the brush roller speed and the length of brush wire were taken as three factors influencing the working quality. The quadratic polynomial response surface regression model was established, and the influence of various factors on the response value was analyzed. From the regression model and variance analysis of regression equation, it could be seen that: lower moving speed, moderate brush roller speed, and shorter brush wire led to higher picking rate; Lower moving speed, lower brush roller speed, and longer brush wire led to lower breakage rate; Higher moving speed, lower brush roller speed, and longer brush wire led to lower impurity rate. The experiment results also showed that the significant effects of moving speed, length of brush wire and brush roller speed on increasing the picking rate were in a decreasing order. The significant effects of brush roller speed, length of brush wire and moving speed on reducing the breakage rate and the impurity rate were in a decreasing order. At the same time, the factors were multi-objective optimized comprehensively, and the optimization results were verified by experiments. The results showed that the optimum parameters were: 0.72 m/s for the moving speed, 372 r/min for the brush roller speed and 57 mm for the length of brush wire. Under these conditions, the picking rate was 91.36%, the breakage rate was 0.18%, and the impurity rate was 11.67%. The measured values of each index were in good agreement with the theoretical optimization values, which meant that the model established was reliable and could be used for optimization. The results can provide a reference for further improving the structure design and working parameters optimization of the brush-roller castor harvester. [ABSTRACT FROM AUTHOR]

As a main grain production equipment, the combine wheat harvester plays an important role in grain production, and its technological development level is an important indicator of the degree of agricultural modernization. However, during the harvesting process, the working parts of the harvester interact with the crop to be harvested, so that the dust originally attached to the surface of the crop is disturbed and separated from the surface of the organism, forming floating and flying dust, some of which are scattered around the harvester, seriously affecting The driver’s body is healthy; some infected plants carry diseased dust, which is more harmful to the human body; more dust is dispersed in the air with the wind, causing a wider range of air pollution and increasing the amount of inhalable particles in the air. This has become one of the sources of air pollution during the crop harvest season. In order to understand the dust generation status and the characteristics of the dust composition, this paper first conducts the dust concentration and distribution test on the operation site of the combine wheat harvester .The result is as the header and tail of harvester are the main areas where dust is generated, Excessive dust mass concentration will harm the health of workers .The characteristics of the dust sample was tested results as follows: the proportions of dust with a particle size of 10μm and 100μm or less are 45% and 92%, the dust is mostly composed of minerals, grease and carbohydrates. The dust measurement test revealed for the first time the dust generation and dust composition characteristics of combine wheat harvester operations in the rice-wheat (oil) rotation area in southern my country. On this basis, a dust suppression system installed on the combine wheat harvester was designed. The system adopts the working principle of negative pressure dust suction and filter cartridge dust collection. The system utilizes the power of the existing combine wheat harvester and can change the working parameters of the fan at any time to meet a variety of field working conditions. Conduct field tests on the dust suppression system. Through theoretical analysis to determine the main factors that affect the efficiency of the dust suppression system. Taking the harvester header dust suppression efficiency and harvester tail dust suppression efficiency as the test indicators, and the harvester speed, fan speed and environment humidity as the test factors. Using Box-Behnken central combination test method, the three-factor and three-level test are carried out. A mathematical regression model of various factors and test indicators was established. Through variance analysis and response surface analysis, the influence of harvester speed, fan speed and environment humidity on the test indicators is obtained. Use Design-Export8.0.6.1 data analysis software to fitting and optimization analysis of the test results, the optimal parameter combination is obtained as follows: harvester speed 3.73 km/h, fan speed 3 507 r/min, and ambient humidity 56%. On this condition, the efficiency of the header dust suppression is 76.8%,the efficiency of the tail dust suppression is 79.6%. The optimal working parameters are tested and verified to verify the feasibility of optimizing the optimal parameter combination, the minimum fan speed of the dust suppression system to meet the dust suppression requirements under difficult working conditions is 3 332 r/min. This research can provide a basis for the design of the harvester dust suppression system. [ABSTRACT FROM AUTHOR]

Application of chemical fertilizer is an important part in the process of crop production management. The research showed that precise application of chemical fertilizer had great significance to improving the utilization rate of fertilizer and reducing the amount of fertilizer application. The outer fluted roller fertilizer apparatus is the key carrier in the process of precise variable rate fertilization. In order to optimize the fertilizer performance of the existing outer fluted roller fertilizer apparatus comprehensively, the discrete element simulation technology, orthogonal test and 3D rapid prototyping technology were used in this paper. The straight flute wheel structural was taken as research object, and influence regularity of 4 key structural parameters such as groove wheel radius, groove numbers, effective working length and groove section on fertilizer performance was analyzed. A discrete element simulation platform was set up in this paper for outer fluted roller fertilizer apparatus, which mainly consists of fertilization bin, fertilization box, the outer groove roller, fertilization tongue, fertilization pipe, soil ground and fertilizer particles. In the simulation test, the advancing speed of outer fluted roller fertilizer apparatus was 0.5 m/s, the working height was 500 mm, and the rotation speed of outer fluted roller was 20 r/min. The coefficient of variation of the fertilizer was selected as the performance evaluation index of outer fluted roller fertilizer apparatus. The test results of the interaction of 3 factors showed that there was no interaction between groove wheel radius and groove numbers, and between effective working length and groove numbers, there was a certain interaction between groove wheel radius and number of the grooves. The L18（37) standard orthogonal table was selected according to the result of interaction. The orthogonal result showed that factors affecting fertilizer performance, from importance to secondary, mainly include groove numbers, groove wheel radius, effective working length, interaction between groove wheel radius and groove numbers, and groove section. The groove numbers had very significant influence on fertilizer performance. The groove wheel radius had significant influence on fertilizer performance. The effective working length, interaction between groove wheel radius and groove numbers, and groove section had no significant influence on fertilizer performance. The optimum combination of parameters is that the groove numbers is 7, the radius of grooves is 30 mm, the effective working length is 20 mm, and the groove section is circular-arc, and the coefficient of variation of the uniformity of fertilizer for this type of outer fluted roller fertilizer apparatus is 1.75%. In order to test the simulation structure parameters optimization results of outer fluted roller fertilizer apparatus, a bench test was carried out under the optimal combination of structural parameters. The bench test mainly consisted of fluted roller fertilizer apparatus, power motor of conveyor belt, power motor of external groove, control box, conveyor belt and ruler. The experimental results showed that the coefficient of variation of fluted roller fertilizer apparatus is 5.48%. Considering that there may be some errors in the bench test, the results of the bench test were basically consistent with the simulation results, which proved that the discrete element method is feasible to optimize the structural parameters of fluted roller fertilizer apparatus. This research results can provide references for optimizing the structural parameters of fluted roller fertilizer apparatus and improving the performance of the fertilizer [ABSTRACT FROM AUTHOR]

The degree of automation of domestic combine harvester is low, and the operation is complex, it is difficult for workers to understand the actual adjustment of working parts. Crop height, crop length, height of the ground and the lack of consistency in course of project led to the continuous adjustment of harvester's joystick. The traditional operation method, in which experiences are excessively relied on, cannot meet the requirements of automatic operation of domestic-made combine harvester. The current operation method is an obstacle to the development of the automatic control of the combine harvester. In this paper, a device of adjusting combine harvester header parameters was designed. The header parameters include height of header, height of reel, position of reel and speed of reel. The control function of header parameters adjusting device is to adjust height of header, height of reel, position and speed of reel. The header parameter adjusting device was composed of sensor modules, PLC control units, display modules, key module, header drive parts module and so on. The sensor modules were used to detect the parameter of header which include height of header, height of reel, position of reel, speed of reel and forward speed. Sensor modules detect the signal inputed into PLC control unit. PLC control unit is the core component of the adjusting device. PLC performs data operation and processing. Using touch display screen as human-computer interaction tools, which communicates with PLC. The display interface includes parameters displaying and setting, and displayed parameters include header parameter, operating speed, crop height and so on. The key module adopts self-reset and self-locking switch to realize manual and automatic function signal input. At the same time, PLC receives the key information and make judgments, and then sends the control signal to drive header hydraulic system to carry out the movement of the mechanism. Header drive parts modules include lectromagnetic directional valve and proportional solenoid valve, which adopts the hydraulic control principle. High reel speed has a large impact on crop yield and increase grain losses. It is difficult to push crops to header and proceed to the next step of threshing, clearing and collection at low reel speed, and it is difficult to match the change of operation speed with the reel speed. In this paper, an automatic control method of reel speed was presented. By analyzing the working process of reel, a mathematical model of reel speed was established, and fuzzy PID algorithm is used to realize the automatic control of reel speed. The header parameter adjusting device was installed on the test prototype, and the regulatory tests, data records and data analysis were carried out. The test results showed that header height, reel height, reel position and reel speed could be electrically controlled by the header parameter adjusting device. Relative adjustment errors of header height, reel height, reel position and reel speed were 7.4%, 3.4%, 2.0% and 7.8% respectively. The operation speed of maximum relative error was 3.4%. The response time is less than 0.8 s, and the adjustment time is less than 1.7 s. The system was proved to meet the design requirements of header parameter controller of combine harvester. The research results can be applied in intelligent operation of combine harvester. [ABSTRACT FROM AUTHOR]

Automatic harvesting of fruits and vegetables is a key process to realize the automation and intellectualization of agricultural production, which can reduce production costs and improve the production efficiency. Tomato is one of the most fruits and vegetables planted in China. The researches on tomato harvesting robots are focused on the single fruit harvesting. The end-effector of the harvesting robot touches the tomato fruit directly and picks one tomato once during harvesting, so the tomato fruits are easy to be damaged and the harvesting efficiency is very low. To overcome the above shortages of the single fruit harvesting, the method of the tomato cluster picking was presented, and the determination method of picking point was developed based on the corner detection on the tomato stem skeleton for the binocular vision system of the tomato cluster picking robot in the paper. The test platform of the vision system was set up and the experiments on the determination of the picking points have been conducted. In the paper, the color images of the tomato clusters were collected in greenhouse in the agricultural production base. The target tomato cluster was segmented from background by OTSU method according to the color features of the tomato clusters and denoised by the morphologic method and threshold method. The centroid of tomato fruit cluster was obtained by enclosing rectangle method. Furthermore, the rectangle region of interest of the target stem was recognized according to constraint relationship between the fruit cluster and the fruit stem, which included the whole stem of the target tomato cluster. Converting the RGB (red, green, blue) color channel map to the HSV (hue, saturation, value) channel map, there are different grayscales between the stem and the background. The target stem of the tomato cluster was separated from background by using the gray difference of H channel and denoised by morphologic method, median filtering method and extracting the maximum connected region. To avoid the effects of the irregular stem on the picking point determination, we abstracted the stem skeletons by Zhang’s thinning algorithm to simplify the stem original shape and extract the kernel information of the stem, and then, the Harris algorithm was applied to extract the corner points of the skeleton, and the corner points were sorted from large to small according to the vertical axis coordinates. The picking feature points on the target stem were obtained by averaging pixel coordinates of the 5 corner points. Sixty groups of experiments on the determination of picking points of the tomato cluster were carried out on the binocular vision test platform. The results show that the success rate of position information obtaining of the picking point on the stem is 90%. Comparing X and Y coordinates data of the picking point and centroid of the tomato fruit clusters, the X coordinates of the picking feature points vary in small range, while Y coordinates vary within wide limits, which results from the main stem growing in longitudinal direction. The mean absolute value of the pixel deviation of the Y coordinates is 21. The research provides the basis for locating the picking point on the stem for the tomato fruit cluster picking robots. [ABSTRACT FROM AUTHOR]

With the rapid development of agricultural aviation, electric multi-rotor unmanned aerial vehicles (UAV) for planting protection are favored in plant protection operations due to their advantages of vertical take-off and landing, air hovering, and easy operation. However, because of its low aerodynamic efficiency, there are currently problems such as low loading mass and short battery life, and it is still necessary to optimize and improve it. The lift characteristics is one of the important parameters for the performance test of the multi-rotor UAV. However, few tests have been conducted on the lifting characteristics of multi-rotor UAV. How do we comprehensively evaluate the lifting characteristics of various types of multi-rotor UAV and make comparisons and judgments on the performance of multi-rotor UAV. At present, there are no standards to follow. Only by clearly defining the evaluation index for lift performance, and by standardizing the test methods and evaluation criteria, the performance of the multi-rotor UAV can be judged and the suggestions for optimization and improvement can be given. Based on the existing research results, this paper considered the functional effectiveness criteria of helicopters combining economy, weight reduction, and heat transfer. A method of test and evaluation for the lift characteristics of the semi-tethered multi-rotor UAV is proposed. It includes performance testing semi-tethered platform, lift characteristics test method and index, and lift characteristics evaluation method. In order to verify the feasibility of the method, the performance test of 3 different models (four-rotor, Type I; six-rotor, Type II; and eight-rotor, Type III) was carried out. The test results show that the 3 models have great difference in power load, weight efficiency and thermal efficiency ratio. Type III is the best in power load, 7.6 mN/W larger than the worst Type I. The best Type I is 0.33 larger than the worst Type Ⅱ in weight efficiency. The best Type III is 10.5 N/°C larger than the worst Type I in thermal efficiency ratio. It reflects the difference in motor and propeller selection and structure of the 3 models of aircraft during the design process, thus showing difference in the performance of the whole machine. On the basis of the above index test, combined with the mathematical model of multi-rotor UAV power system, a scoring method is put forward to evaluate the lift characteristics of the multi-rotor UAV using the power load, weight efficiency and thermal efficiency ratio. The results of the comprehensive score of the 3 types are as follows: Type III > Type I > Type II. The results show that the proposed evaluation method can effectively evaluate the lift characteristics of different types of multi-rotor UAV. It can more objectively and accurately assess the technical level of multi-rotor UAV and strengthen the management of multi-rotor UAV in use. The test and evaluation method presented in this paper can not only be used to evaluate the performance of the multi-rotor UAV, but also provide a reference for the further improvement of the model performance. Of course, in the performance evaluation of multi-rotor UAV, the improvement of power load, weight efficiency and thermal efficiency ratio cannot be excessively pursued, and the balance of technical performance, reliability performance, safety performance, and economical efficiency should be upheld. [ABSTRACT FROM AUTHOR]

Under the full amount of straw returning mode for wheat-maize rotation cropping areas in Huang-Huai-Hai Plain of China, not only the wheat straw mulch in the field is large, but also it has good toughness, and the effect of straw grinding is poor. In addition, the soil is more viscous. When the field operation is driven by the traditional wheel drive, it is easy to have straw winding and congestion, which is easy to break when seeding. At present, the corn seeder mainly adopts the ground wheel driving seeder and pneumatic seeder, and the land wheel driving seeder is transmitted by the earth wheel, driving the seed row shaft to rotate and arrange seeds, When the field soil viscosity and straw coverage are large, the driving part can not work normally. Pneumatic corn planter is mostly used in large farms, which are more expensive and not suitable for domestic use. In order to reduce the rate of missed seeding and improve the precision of maize sowing, it is necessary to develop a reliable and active corn precision seed metering control system. To solve these problems effectively, this paper takes a common spoon-wheel corn seeding device in the market as the research object, and a kind of active electronic control corn seeding meter system is designed. This electronic control system consists of control box, touch display interface, rotary encoder, GPS speed sensor, brushless DC motor, driver and commutator reducer. When the system works, the USART HMI four-wire touch serial port man-machine interface is used to input the theoretical expectation of the controller to the controller, using the GPS speed sensor to collect the working speed of the machine, in combination with rotary encoder, and the operation speed of the feeder is collected in real time. To ensure the quality of work and improve the ability to resist interference, based on the double closed-loop fuzzy algorithm, the PID parameters are self-adjusted to get the target speed of seed metering device. The corresponding PWM duty cycle of the controller is adjusted to achieve the real-time control of the motor speed through machine operation speed and achieve precise seed metering. The results of bench test showed that the variation coefficient of the actual rotational speed was less than 10.0% when the theoretical rotation speed was 6 ~ 54 r/min, and the actual rotational speed was small in the vicinity of the theoretical rotational speed, which met the control requirements. When the speed was 3 ~ 5 km/h under the set spacing value, the plant distance qualified index was > 94.0%, and the leakage index was < 3.0%. When the vehicle speed was 6 ~ 8 km/h, the plant distance was greater than 90.0%, and the seeding index was less than 4.5%. Field validation results showed: under the full amount of straw returning mode for wheat-maize rotation cropping areas in Huang-Huai-Hai Plain, when the maize row control system was in operation, the qualified index was greater than 87.75%, and the average was 90.89%, and the seeding index was less than 4%, with an average value of 2.54%. In comparison with the common spoon-wheel corn seeding device in the market, the qualified index was increased by 2.12 percentage points, and the seeding index was decreased by 4.32 percentage points, and the seeding performance was good, which met the requirements of corn agronomic planting. Under the full amount of straw returning mode for wheat-maize rotation cropping areas in Huang-Huai-Hai Plain of China, not only the wheat straw mulch in the field is large, but also it has good toughness, and the effect of straw grinding is poor, and in addition, the soil is more viscous. In this paper, the research of electronic control system for seed meters for maize planting can effectively improve the quality of the row and provide a reference for the development of high speed actuator control system. [ABSTRACT FROM AUTHOR]

As an important type of non-road machinery, agricultural machinery plays an important role in national economy. At present, the main power source of agricultural machinery is diesel engine. However, the inherent combustion mode of diesel engine leads to large amounts of pollutant emission such as particulate matter (PM) and nitrogen oxide (NOx), and PM and NOx can cause great damage to human health and ecological environment. Therefore, exhaust emission control technology research for agricultural machinery is of great significance. From 3 aspects, this paper elaborates agricultural machinery emission legislation, individual technical routes to reduce agricultural machinery emissions, and combined technical routes to meet more stringent emission limits. Agricultural machinery emissions legislation part analyzes regulations of the EU (European union), the United States and China on exhaust emission limits, test cycles requirements, and their differences. The current agricultural machinery emission legislation for agricultural machinery in China is Stage III. Compared with the standard of Stage IV implemented by the EU and the standard of Tier IV implemented by the United States, exhaust emission limits of China III are relatively relaxed. Legislation of the EU, the United States and China for agricultural machinery increases the non-road transient cycle (NRTC) from Stage IIIB, Tier IV and China IV, respectively. Unlike the EU, China and the United States stipulate that agricultural machinery diesel engines of non-constant speed below 19 kW can also be tested under the cycle of 6 working conditions. In EU and China, the final measuring results of exhaust emissions consist of 10% of the cold start and 90% of the hot start, while the United States reduced the proportion of cold start test cycle results to 5%. Individual technical routes of agricultural machinery emission control mainly include oil technologies, engine purification technologies, and exhaust after-treatment technologies. Among them, oil technologies include improving the quality of fuel and lubricating oil, use of alternative fuels, and so on. Engine purification technologies include diesel engine optimization design for agricultural machinery, supercharging and supercharged intercooler, fuel injection optimization, and EGR (exhaust gas recirculation). Exhaust after-treatment technologies include DOC (diesel oxidation catalyst) technology, DPF (diesel particulate filter) technology and SCR (selective catalytic reduction) technology. Oil technology is a prerequisite for agricultural machinery exhaust emission control, while engine purification technology is the foundation. Advanced exhaust after-treatment technology is the key to meet stringent emission limits for agricultural machinery. Combined technology routes summarize the methods to meet China III and IV emission limits and the latest foreign emission limits. Diesel engines using the "optimized combustion + SCR" route save 5%-7% fuel compared with diesel engines using the "EGR + DPF/CDPF (catalytic diesel particulate filter)" route. Deducting urea consumption, the former route still saves 2%-3% fuel. "Optimized combustion + SCR" route is used in the EU commonly, while "EGR + DPF/CDPF" is usually used in the United States. Considering actual situation in China, there is still much room for improvement in fuel quality, but urea production is very common, so the implementation of China IV legislation prefers SCR. Of course, to find proper routes for agricultural machinery exhaust emission control, it needs to consider the power of agricultural machinery diesel engine, displacement and specific use of the environment, and other requirements. Finally, this paper summarizes the prospects of agricultural machinery emission control technologies. To meet the future China IV limits, it is a significant measure to install an exhaust after-treatment catalytic converter for agricultural machinery. Developing an integrated exhaust after-treatment catalytic converter with low cost and high purification efficiency may become an important research direction for the future emission control of agricultural machinery [ABSTRACT FROM AUTHOR]

Harvesting machinery has been the focus of agricultural equipment in recent years, especially the picking manipulator. Traditionally, the picking manipulator consists of series multi-link structure, which owns good motive performance during assignment of fruit harvesting. However, the multi-link picking manipulator is difficult to cross through the complicated agriculture environment. Thus, this paper proposes a novel continuum picking manipulator for the agricultural harvesting. The continuum picking manipulator is a novel agricultural operation robot with full flexibility and self-adaptability, which provides a good ability to complete various tasks in the complicated agriculture environment. The main structure of the continuum picking manipulator consists of 4 fiber-glass rods, several guide shelves and rubber tubes. The fiber-glass rods cross the hole of the guide shelves and rubber tubes that form slide joint, and the guide shelves are distributed among the continuum picking manipulator uniformly through the separation of the rubber tubes. The movement of the continuum picking manipulator is fulfilled by 4 servo driven modules which are composed of ball screw slipway and servo motors. The space motion and the flexibility feature are due to the combination of bending motion of the fiber-glass rods, which are achieved through controlling 4 driven modules harmoniously. Although the flexible features of the continuum picking manipulator bring the considerable dexterousness in the process of fruit harvesting, the loading posture of the continuum picking manipulator has deformed, which affects motion performance of the continuum picking manipulator due to the flexibility feature. Thus, this paper presents an innovative method to solve the problem of load posture deformation at the free end of the continuum picking manipulator. Firstly, the kinematics is obtained and the workspace is analyzed. Secondly, the continuum pick manipulator is simplified by static analysis. Finally, the theoretical model of the loading posture is set up according to the theory of large deflection and the principle of unit force. The posture function of continuum picking manipulator and the free-end coordinates can be calculated based on the presented theoretical model, and the input variables are bending angle, rotation angle, length and the load. Further, the theoretical model is verified through the systematic multi-parameter experiments by using the distortionless camera with 50 mm focal length, and the load posture error between theoretical and experimental values is no more than 7.8%. Finally, the influences of different posture parameters and the load on the model errors of the continuum picking manipulator are discussed. The error increases with the load, due to the gravity effect and the structure of the continuum picking manipulator. The maximum free end position error is 7.8% and the minimum error is 3.8%. The presented theoretical model is featured with less calculation to fit on-line real-time control of the manipulator. Furthermore, this model can extend to multi-section continuum picking manipulator with consideration of each lower section is a payload of its upper sections. [ABSTRACT FROM AUTHOR]

At present, the supply and demand information in the emergency operation of agricultural machinery is asymmetric. Without the scientific and reasonable emergency allocation plan, agricultural machinery department could not guide scheduling and allocating of agricultural machinery timely and effectively in the emergency situation. To solve the above problems, models and algorithms of emergency scheduling and allocating based on intelligent agricultural machinery platform are studied in the paper. The intelligent agricultural machinery platform, which is integrated of GPS (global positioning system), information communications, networking, Internet of things and other related technologies, can realize real-time data collection, data transmission, data storage, data calculation and decision-making of agricultural machinery and farmland. Emergency scheduling and allocating problem based on intelligent agricultural machinery platform needs to establish one kind of mapping relation between farmlands and agricultural machinery. The main influencing factors including time limit, location, distance and operation ability in emergency deployment are analyzed and the mathematical model of the emergency scheduling and allocating problem is established with minimizing costs and losses as scheduling and allocating objectives. According to the model, the emergency scheduling and allocating algorithm based on the shortest-distance first algorithm (SDFA) and the emergency scheduling and allocating algorithm based on the max-ability first algorithm (MAFA) are proposed in this paper. The former one is prior to allocate the agricultural machinery to the nearest farmland and the latter one is prior to allocate the agricultural machinery with the maximum operation ability. Taking the emergency operations of wheat combine harvesters in Handan City, Hebei Province as the research objects, the emergency scheduling and allocating scheme is calculated by using the algorithms proposed in the paper. The results show that the cost of MAFA algorithm is lower than that of SDFA algorithm when the amount of agricultural machinery is sufficient, and therefore the MAFA algorithm is more suitable for the situation with enough agricultural machinery. Costs and losses of SDFA algorithm are lower than those of MAFA algorithm when the amount of agricultural machinery is insufficient, so SDFA algorithm is more suitable for the situation with the shortage of agricultural machinery. Further analysis shows that when the amount of farmland is 6, the average running time of the emergency scheduling and allocating algorithm with non-cooperative game algorithm (NCGA) proposed in the existing literature is 3.215 s, the average running time of both MAFA and SDFA is less than 2.4 s, and the performance has been improved by more than 25%. When the amount of farmland is 10, the average running time of NCGA is 4.286 s, the average running time of both MAFA and SDFA is less than 2.7 s, and the performance has been improved by more than 37%. When the amount of farmland is 15, the average running time of NCGA is 5.369 s, the average running time of both MAFA and SDFA is less than 3.3 s, and the performance has been improved by more than 39%. When the amount of farmland is 30, the average running time of NCGA is 6.485 s, the average running time of both MAFA and SDFA is less than 3.8 s, and the performance has been improved by more than 41%. The experimental results show that the 2 emergency scheduling algorithms have better operational performance and can provide scientific basis to the emergency allocation and decision analysis for agricultural machinery management department. [ABSTRACT FROM AUTHOR]

As the main transportation equipment in mountainous orchards, monorail conveyers have strong climbing capacity and high reliability. However, monorail conveyers in working status can be invisible frequently because of tree shades. It is impossible for operators to monitor a working monorail conveyer with a remote control in real time. Thus the monorail conveyer should have the capacity of arriving at the designated locations autonomously. The key technology is to locate the conveyer on the monorail accurately. In recent years, there has been growing attention on the technology of ultra high frequency RIFD (radio frequency identification) location, which is based on RSSI (received signal strength indicator) data. The ultra high frequency RIFD location has been applied in many fields including workshop inspection, warehouse management and staff supervision. However, these applications are carried out in indoor environment. There is little research on locating agricultural implements using ultra high frequency RIFD. Considering the application requirement of locating the conveyer on the monorail accurately, experiments of the monorail conveyer location awareness have been carried out in this paper, which is based on the RFID RSSI data. The RFID equipment used in this paper include an XC-RF807 UHF RFID reader with 2 separated unidirectional antennae and several XCTF-8405 anti-metal passive tags, which are provided by Invengo Technology Pte. Ltd, Shenzhen, China. The operating frequency of reader is 902-928 MHz and the transmitted power can be varied from 15 to 36 dbm. Firstly, RFID communicative features are analyzed. The approach of conveyer location is proposed by comparing the RSSI data between dual antennae and dual tags, which aims to reduce the noise interference in conveyer location. Then the energy transferring location model and path loss location model are formulated. Secondly, several experiments are carried out in the citrus orchard, which is located in the China Agriculture Research System, Guangzhou, China. The 2 significant setting parameters of RFID equipment, i.e. the optimal perpendicular distances between RFID antenna and the tag on the monorail, and the optimal horizontal distances between tags on the monorail, are obtained in the experiments of RFID single antenna. Parameters of the 2 location models are fitted to be applicable to experiment environment through the analysis of RSSI data, which can be obtained in the experiments of RFID dual antennae. Finally, the results of performance experiments on location models show that the approach of conveyer location, which is implemented by comparing the data of dual antennae and dual tags, can reduce the noise interference effectively. It can reduce the location error and improve the location system accuracy, but the interference cannot be eliminated completely. The experiment results also demonstrate that reducing the distance between dual tags on the monorail, which increases the density of deployed tags, is not a good way to improve the location system accuracy. The optimal horizontal distances between tags, and the optimal perpendicular distances between RFID antenna and the tag on the monorail are 45 and 20 cm, respectively, and the optimal coefficients in path loss location model are 63.19 and 2.988, respectively, which are applicable to the experiment environment. The varying lengths of conveyers should be considered when different types of conveyers are used. Under the optimal conditions, the minimal average location error is 1.077 4 cm by using the path loss location model, and the minimal location error is 0.017 0 cm by using the energy transferring location model. In order to further verify the effectiveness of the proposed approach, another experiment is carried out in Germplasm Resource Garden of Southern Subtropical Fruit Trees, Guangzhou, China. It shows the similar location results. The research in this paper verifies the feasibility of locating the conveyer on the monorail accurately by using ultra high frequency RIFD equipment. The proposed location approach can improve the safety and reliability of working monorail conveyers. It also can provide accurate data support for applications including multiple transportation tasks planning and scheduling. [ABSTRACT FROM AUTHOR]

The banana stalks are rich in fiber, and the existing returning machines for banana straw and stubble crushed in China have generated a few problems such as overly severe cutting resistance, the fiber of banana straw winding crushing blade roller on the returning machine, working on the unstable condition and serious fuel consumption. In order to deal with the above problems which the existing choppers met with in the working process, with the help of theoretical study and the analysis on the planting model for banana in Hainan Province, this paper put forward a returning method that the moving knives on the front knife roller were used to crush banana straws and the flail knives on the back knife roller were used to break stubble under the earth. The rotational direction of stubble crushing roller in the returning machine was same to the forward direction of the machine providing power, while the rotational direction of straw crushing roller was contrary to that of stubble crushing roller. On the basis of establishing theoretical model and the analysis on the planting model for banana in southern China, the key shaped parameters of the sliding-cutting blade and the structural parameters of crushing blade rollers were determined respectively. Besides, the sliding-cutting and anti-twining returning device for banana straw was put forward. The overall structure and working principle of sliding-cutting and anti-twining returning device were described. The performance of crushing banana straw and the power consumption were evaluated by simulating the breaking operation of banana straw in farmland through a bench test driven by double electric motors. The machine was composed of electrical motors, a tractor powered by electricity, the frame of machines, the straw crushing device and the stubble crushing device. Through Design-Expert software, a quadratic orthogonal rotating experiment was performed. Based on the variance analysis and regression fitting, a multiple regression equation was gained, presenting the effects of the working speed of the returning device, the rotating speed of rotating roller of moving knives and the rotating speed of rotating shaft of stubble breaking on the qualified rate of straw crushing and power consumption. It could be seen that the rotating speed of rotating roller of moving knives had the most influential effect, followed by the rotating speed of rotating shaft of stubble breaking, and the working speed of the returning device had the least influence on the qualified rate of straw chopping. The operation condition was optimized by applying the response surface method. The optimum factors for straw and stubble crushing process were as follows: The rotating speed of rotating roller of moving knives was 1 600 r/min, the rotating speed of rotating shaft of stubble breaking was 500 r/min, and the working speed of the returning device was 1.39 m/s. Based on the theoretical analysis, the higher qualified rate of straw crushing was achieved under the faster rotating speed of rotating roller of moving knives. The smaller power consummation was obtained under the lower rotating speed of rotating roller of moving knives and the lower rotating speed of rotating shaft of stubble breaking. Under the optimal condition, the corresponding qualified rate of straw crushing and power consumption were 95.2%, and 4.96 kW, respectively. The differences between the experimental and the analytical values of the qualified rate of straw chopping and power consumption were 0.31 percentage points and 0.27%, respectively, which indicated that the software analytical value was in great agreement with the experimental value. And by field test, qualified rate of straw crushing of machine proposed in this paper was higher by 1.94 percentage points and power consumption was lower by 11.3%, compared with vertical flail banana stalk crushing machine. Its successful implementation can greatly improve the production efficiency for crushing banana straw and stubble on one hand, and on the other hand prevent the pollution brought by deserted banana straw putridity. [ABSTRACT FROM AUTHOR]

In the current, ultrasonic atomization technology is becoming the key technology of ultra-low volume spray technology in facility agriculture. In order to systemically research the factors affecting the control effect of ultrasonic pneumatic spray on rice planthopper, in this study, the ultrasonic pneumatic spray test platform for rice planthopper was built. This test platform simulated the growth environment of rice planthopper by controlling the temperature, air flow and soil environment. The temperature of the test platform was adjusted by the heater through the PID (proportion, integral, derivative) control system. The air flow was controlled by the electric fan which was placed on the side. The soil was taken directly from the experimental plot in the Yangzhou University. The effects of different operating parameters such as liquid concentration, spray height, moving speed and strength value on the performance, wide width of spray and droplet size of ultrasonic aerosol were studied, and the control effect of ultrasonic aerodynamic spraying on rice planthopper was tested and verified. The biological dye Ponceau-G, which was used as tracer, and distilled water were mixed to be the hydrojet that had the same density and viscosity as pesticide. This kind of hydrojet can leave a trace that is not easy to spread on the qualitative filter paper. The performance and wide width of spray could be qualitatively observed on filter paper. The spray droplets were collected by the white oil which was used as the collection liquid. The droplet size was obtained by 500 times microscope and measuring micro ruler. The rice planthopper and rice seedlings from the Ecological Laboratory of Yangzhou University were placed in the test platform, and using the same configuration of imidacloprid, the control effects of ordinary spray and ultrasonic pneumatic spray on rice planthopper were compared. The experimental results show that when the nozzle moves at a speed of 160 mm/s and a flow rate of 5.5 mL/min, the atomization rate is the highest and the atomization effect is better than others. When the flow rate is 5.5 mL/min, the pesticide utilization rate is the highest. The average values of particle size are basically the same at different pneumatic values, all of which are about 25 μm, and when the air pressure is 20 kPa, the width of atomization reaches 240 mm. Because the particle size of the aerosol spray droplets is very small, the wind speed has a great influence on the droplet trajectory, which can ensure the normal operation of the spray in the greenhouse by increasing the air force value. The adhesion effect of droplets on the blade will be affected by spray flow, droplet diameter, wind speed and blade tilt angle. In comparison with ordinary spray, the pesticide utilization rate of ultrasonic pneumatic spray is increased by 35%-45%, and the control effect on rice planthopper is increased by 10%-36%. The experimental results are of guiding significance and practical value to improve the status quo of relatively backward equipment and technology, and to improve the mechanized control technology of chemical pesticide. [ABSTRACT FROM AUTHOR]

4HLB-4 type semi-feeding four-row peanut combine harvester gets 2 ridges (4 rows) at one time, whose productive efficiency is 2 times more than the existing semi-feeding two-row peanut combine harvester. Bar strip screen, woven screen and perforated screen and other traditional screens are widely used in semi-feeding peanut combine harvesting, but in practice, it is found that the traditional screens can not meet the demand of changeable soil moisture content and the requirement of high efficiency. In the application of semi-feeding four-row peanut combine harvester, there are many problems such as high percentages of impurities and loss, and debris blockage. In order to overcome the above difficulties, a stacked elastic steel pole oscillating screen was designed in this paper, and it can transfer dynamic load to the elastic steel pole to motivate elastic vibration of itself, which has a very good breaking and flipping effect on the mixture of peanut and varia on the screen surface and is good for screening operation and improves screening quality and speed effectively. In this paper, the percentages of impurities and loss were taken as the evaluation indices, and the contrast tests for 3 kinds of traditional screens (bar strip screen, woven screen and perforated screen) and elastic steel pole oscillating screen were carried out when the operating speed was 0.8, 1.0 and 1.2 m/s respectively. The test results showed that cleaning effect of elastic steel pole oscillating screen was better than the other 3 traditional screens in 3 operation speeds. Based on the single factor experiment, vibration frequency of elastic pole screen, diameter of elastic pole, altitude of elastic pole screen, mounting angle were selected as influencing factors. The four-factor three-level quadratic regression orthogonal test was carried out by using Box-Benhnken central composite test method. Two polynomial regression models about percentage of impurities and percentage of loss v.s. the 4 variables including vibration frequency of elastic pole screen, diameter of elastic pole, altitude of elastic pole screen, and mounting angle were established. Response surface methodology was used to analyze the influence of various factors on percentages of impurities and loss, and the influence factors were optimized. The experimental results showed that different factors and their interactions had different influence on the measured indices. The significant sequence for percentage of impurities was vibration frequency of elastic pole screen > diameter of elastic pole > altitude of elastic pole screen > mounting angle. The significant sequence for percentage of loss was altitude of elastic pole screen > mounting angle > vibration frequency of elastic pole screen > diameter of elastic pole. In order to find the best combination of parameters, the minimum percentages of impurities and loss were taken as optimization targets, a research on parameter optimization of the screen was carried out, and the constraint condition of objective function and parameter variable was established. The optimal parameter combination of vibration frequency of elastic pole screen of 6 Hz, diameter of elastic pole of 3 mm, altitude of elastic pole screen of 7 mm and mounting angle of 2.8° was obtained using optimization module of Design-Expert data analysis software. Field experiments were carried out with the above optimized parameters, and the percentage of impurities was 2.41% and the percentage of loss was 0.711%. The relative errors of each evaluation index and its theoretical optimization value were less than 5%. The research results can provide references for the perfect design and operation parameter optimization of 4HLB-4 type semi-feeding four-row peanut combine harvester and cleaning component. [ABSTRACT FROM AUTHOR]

Proper dynamic modeling is essential for the design and control of paddy field levelers which maintains a level plow while working regardless field unevenness. The simplified rigid multibody method of dynamic modeling, of which modeling and simulation can be handled by hand generally, does not work well in that they do not produce satisfactory results, and there is not easily available method for verifying the simulation results. This paper proposes a flexible multibody approach for the paddy field modeling and simulation, and a method for model verification based on high speed camera measurement. For the former method, it is simplified to decide which bodies to be classified to be rigid or flexible and the related constraint types by studying the structure and theory of the multibody system, while leaving the tedious tasks of building differential-algebra equations and equation solving to the computer-based simulation tools; and the latter method features a non-contact, stereo image way to find the 3D (three-dimensional) position of center of mass and attitude angles of a rigid body through positioning multiple surface points. 1) Modeling. By analyzing the structure and summing up the past experiences, considering that the 3 parallel rods hanging the installation block and plow showed significant flexibility in many directions, a flexible multibody system with 2 rigid bodies (plow and installation block) and 1 flexible body (representing the 3 rods with a flexible beam) and 3 revolute joints in between was built. It was assumed that the tractor body was stationary, which helped to simplify the subsequent simulation and verification by reducing the flexible beam to be a cantilever beam. 2) Simulation. The MapleSim was used to perform the simulation. By introducing the main multibody library models, i.e. flexible beam, rigid body and rigid body frame, and following general modeling procedures, the leveler model was expressed into MapleSim environment. The model parameters were determined by measurement (for dimensions) and computer software like CATIA (computer aided three-dimensional interactive application) and ADAMS (automatic dynamic analysis of mechanical systems) (for mass values and inertial momentums). Among simulation results, curves for the position of the leveler's center of mass and inclination angle were produced. 3) Verification. Formulae finding the position of mass center and attitude angles of the plow by multiple surface points' 3D positions (at least 3 points that do not fall on the same straight line) were proposed, and the surface points' 3D positions were determined by the stereo imaging system composed of 2 high-speed cameras and the professional image analysis software TEMA. Laboratory tests on specially designed fixtures were conducted, which produced the plow's 3D position of mass center and its inclination angle as measured results to be used against the simulated results for model verification. The verification showed that the 2 kinds of results generally coincided with each other well, indicating that the modeling, simulation and verification method proposed is feasible and practical, though a closer check showed the inclination curves agreed quite well, but the position curves of mass center revealed a maximum deviation of 10 cm at times. Some causes for the difference were proposed. The method proposed in this paper, which includes modeling by structure analysis, simulation using software, and verification by measuring 3D position of center of mass and attitude angles of a rigid body using high-speed cameras, is feasible and applicable to similar mechanical virtual prototyping applications featuring modeling, simulation and verification. [ABSTRACT FROM AUTHOR]

Agricultural machinery purchase subsidy is an important agrarian policy, its policy effect has been widely concerned by scholars. However, very few studies have discussed the spatiotemporal difference, agricultural machinery types difference and endogeneity of subsidy’s policy effect. The purpose of the present study is to make policy effect evaluation more accurately, and analyze the spatiotemporal difference and agricultural machinery types difference of policy effect. Different from existing studies, the present study uses a large sample collected from 15 089 observations in 3 287 households at 18 provinces from 2008 to 2018 by China agriculture research system (rapeseed) farmer fixed observation point and employs unbalance panel fixed effect model, panel high-dimensional fixed effects model, Box-Cox model, quantile regression model to calculate the differential policy effects between different year, topographic regions and types of agricultural machinery purchase subsidy on farmer’s agricultural machinery self-investment. In addition, instrumental variables fixed-effects panel-data models, Tobit fixed-effects panel-data models and Heckman sample selection models were used for the robust test. The result showed that 1) On the whole, agricultural machinery purchase subsidy had an obvious incentive effect, effectively promote farmer’s agricultural machinery self-investment, the marginal effect of agricultural machinery purchase subsidy on farmer’s agricultural machinery self-investment was 2.530 8. 2) The effect of subsidies varies significantly between plain and non-plain areas. Subsidy’s marginal effect in plain county was 1.408 5, subsidy’s marginal effect in hill and mountain county was 3.108 2. Subsidy policy was more effective in hill and mountain areas. 3) Generally, subsidy’s incentive effect fluctuated significantly between the years, crowding-out effect was showed in some years. The number of years in which the policy effect declined from the previous year was equal to the number of years in which it rosed from the previous year. 4) On the whole, the subsidy effect was enhanced with the increase of the value of agricultural machinery, and the policy effect was higher for large and medium-sized agricultural machinery. Accordingly, this paper suggested that: 1) In the future, agricultural machinery purchase subsidy should continue to implement. 2) Agricultural machinery purchase subsidy should tilt appropriately to non-plain areas and large and medium-sized agricultural machinery continually. Appropriate R&D subsidies can be given to agricultural machinery production enterprises to research and develop large and advanced machines and suit machines which used in hilly and mountainous areas. Encourage local governments to include large and advanced machines and machines which was suitable used in hilly and mountainous areas into the new agricultural machinery subsidy pilot catalogue timely. Accelerate the transformation and application for new machine products. 3) Adjust or improve the subsidy mode according to the implementation situation and agricultural mechanization development situation. [ABSTRACT FROM AUTHOR]

In order to solve the problem of deep feature extraction of nonlinear feature signal of operation faults of combine harvester and improve the diagnosis accuracy of fault recognition, a method based on Stack Denoising Auto Encoder -Back Propagation neural network(SDAE-BP) model was proposed in this study. Lovol RG50 combine harvester was used as the test prototype, according to the analysis of the working procedure and failure mechanism of each component of combine harvester, NJK-5002C speed sensor was used to collect the rotation speed signal of feeding auger, impurity auger, grain beat auger, fan, threshing cylinder and conveyor chain harrow, and the frequency signal of sickles and straw walker, and the collected data sets were used as the input of the monitoring system. The monitoring system was consist of IPC-610L embedded industrial computer, USB-4711 data acquisition module, EYOYO interactive display screen and LTE-1101J sound and light alarm device. The SDAE model was used to extract the deep feature of the input signal, the extracted deep feature was sent to the BP neural network and then the operation status of combine harvester was classified. During the training process, the first step was to train the DAEs (Denoising Auto Encoder) under different gaussian noises distribution center respectively, after all the DAEs was trained, stacking the DAEs all together and fine-tuning the model’s parameters through the error back propagation algorithm. The noise center of DAE was far away from 0, which meaned that the original data was seriously damaged, the model could learn global coarse grained features, the noise center of DAE was close to 0, which indicateds that the damage degree of original data was low, and the model could learn local coarse grained features, in other words, training each DAE with different gaussian noise centers, the SDAE model would learn both global and local coarse grained characteristics which was of great significant to improve the model’s expressive ability of deep feature. The experiments were carried out in 2018 to verify the proposed method, and the results showed the diagnostic accuracy rate reached 99.00%, which improved by 1.50 and 4.50 percentage points respectively compared with SDAE and BP neural network. The DAE-BP model was updated with the test data of 2019, and tested with the data of 2018 and 2019. The results show that the fault identification accuracy rate of the updated model for the test data in 2018 was 99.25%, and that for the test data in 2019 was 98.74%,which increased by 6.52 percentage points than that of the unupdated model. The model established in this paper can accurately identify the fault type of combine harvester, and has good robustness, which has reference value for the fault monitoring and early warning of rotating machinery. [ABSTRACT FROM AUTHOR]

Sweet potato is an important food crop and energy crop. In order to solve the problems of larger loss rate and high damage rate of 4UZL-1 sweet potato combine harvester during the operation process, a potato connection and conveying mechanism was designed based on the analysis of the structure of 4UZL-1 sweet potato combine harvester and characteristics of domestic sweet potato planting models in this paper. The potato connection and conveying mechanism was mainly composed of a depth limiting mechanism, a digging conveying mechanism, an arc grid conveying mechanism and a scraper chain conveying mechanism. The working parameters were obtained through the kinematic and mechanical analysis of the working process of the mechanism. Aiming at the main evaluation indexes of potato damage rate and loss rate during the transfer and transportation, the Box-Benhnken test was presented on the basis of single-factor test. The angle of the digging conveyor, the conveyor angle of the scraper chain, the conveyor speed of the digging and the conveyor speed of the scraper chain were selected as testing factors. The multiple regression model of evaluation index to each factor was established, and the influence of each factor on operation quality was analyzed, and the optimal structure and operation parameters were obtained. The results showed that the order of the significance influence of factors on potato loss rate from large to small was that the conveyor angle of the scraper chain, the conveyor speed of the digging conveyor, the conveyor speed of the scraper chain and the angle of the digging conveyor. The order of the factors influencing on potato damage rate from large to small was the conveyor speed of the digging, the angle of the digging conveyor, the conveyor speed of the scraper chain and the conveyor angle of the scraper chain. When the forward speed of the machine was 1 m/s, the angle of the digging conveyor was 20°, the conveyor angle of the scraper chain was 68°, the conveyor speed of the digging was 1.2 m/s, and the conveyor speed of the scraper chain was 0.67 m/s, respectively, the potato loss rate was 1.12%, and the potato damage rate was 0.94%. Compared with the predicted values, the relative errors were 3.4% and 1.1%, respectively, the results satisfied the performance requirements of the 4UZL-1 sweet potato combine harvester. The study is benefit for the structure improvement and operation parameters optimization of the sweet potato combine harvester. [ABSTRACT FROM AUTHOR]

Peanut straw is excellent feed for animals. In order to realize the animal feed utilization of peanut straw planted with plastic film, a "three-step" harvesting method (cutting-digging-picking and harvesting) was put forward Specifically, peanut straws is cutted before digging to shorten the peanut plant, reduce the transverse size and increase the pod-straw ratio, which is conducive to the harvest operation. At present, there is no suitable pickup device for peanut harvest after cutting straws. Based on the existing peanut combine harvesting techniques, an elastic-tooth pickup device was designed in this paper. As an important part of peanut combine harvester, the elastic-tooth pickup device was mainly composed of pickup elastic tooth, conveying plate, support plate, installation base of pickup elastic tooth, installating tube, main shaft, etc. The transverse sizes of the post-cutting peanut plants were analyzed by using SPSS software, and the separation distance of the neighboring elastic teeth was determined as 7 cm. Based on the theoretical analysis of the conditions of peanut plants picking and throwing, radius of gyration and rotating speed of the elastic tooth determined as 21 cm and 60 r/min, respectively. Through the analysis of the stress situation during the peanut plant picking, the bending angle of the pickup elastic tooth and the length of the bending part were determined to be 102° and 4 cm, respectively. Through analysis of the movement trajectory of the pickup elastic tooth tips by using Matlab software, the movement trajectory of different rows of elastic tooth tips was calculated, the row number of elastic tooth was determined to be 6. Finally, field experiments of the peanut pickup device were carried out. The results showed that the pickup rate was 98.07%, and the drop rate caused by the pickup device was 1.23%, the operation performance of the pickup device met the requirements of peanut pickup harvest after cutting straws. During operation, there were two main reasons for missing picking, firstly, a small amount of peanut plants after cutting were too short and dropped to the ground from the elastic teeth gap; secondly, during the digging operation, some shallow ditches were formed when the tractor tires rolled on the ground, the peanut plants falling in the shallow ditches could not be picked up, resulting in missing picking. There were three main reasons for the pod drop, firstly, some peanut straws decayed and straws strength decreased; secondly, the peanut pod after straws cutting lost the "protection" of peanut vine, which increased the probability of the elastic teeth hitting the pod directly; thirdly, because a small number of peanut plants could not be picked up at one time, and need to be picked up for 2-3 times continuously, multiple picking and beating increased the drop of pod. This study can provide a basis and reference for the development and improvement of the pickup harvest technique for peanut and other short crops. [ABSTRACT FROM AUTHOR]

In order to solve the problems of limited working environment and low positioning accuracy of mountain orchard monorail conveyer, a set of accurate on-orbit status sensing system for orchard monorail conveyer was designed based on high frequency RFID (Radio Frequency Identification) hybrid speed measurement and positioning method in this paper. The system combined electromagnetic wave positioning with velocity measurement to obtain data from high frequency RFID module. The STM32f103rct6 chip was used as the main control unit of the sensing system, the dual RFID reader was used to read the time difference of the reference location tag groups, the hybrid speed measurement and positioning method was used to calculate the real-time operation status information of the conveyer in real time, and the mobile terminal monitoring software was designed, and the real-time operation status information of the conveyer was obtained through LoRa communication module in order to evaluate the performance of the sensing system, the experiments was carried out in the monorail conveyer test platform, which located in South China Agricultural University. The electric monorail conveyer with 7SYZDD-200 model was used, which designed by China Agriculture Research System. The track in the test platform was circular with 130.59 m. The track was divided into 10 segments according to different track conditions of flat track, band track, uphill and downhill. Experimental results showed that the system could accurately sense the running state information of monorail conveyor on-oubit in real time, but in different track conditions, the test results of the conveyer speed fluctuate greatly. Compared with other track conditions, the average tested speed of the conveyer in the whole course of flat running was 0.49 m/s, and that recorded by the stopwatch was 0.48 m/s, the relative error was 2%. When the distance between tags was 3.42 m, the average positioning error was 6.18 ± 0.60 cm; when the distance between tags was 6.84 m, the average positioning error is 6.46 ± 1.14 cm, which was about 0.94% relative to the distance between tags. The study verified the feasibility of high-frequency RFID based accurate perception of monorail conveyer on-orbit, and improved the safety and intelligence of the transport operation, which can provide reference for the realization of precise operation in orchard production. [ABSTRACT FROM AUTHOR]

A large amount of maize stalks are produced each year, due to the maize is serving as one of the main grain crop in China. Maize straw retention to the field after chopped is widely used in most disposal approaches. However, the currently used single shaft maize stalk chopping and retention machine can not meet the quality requirements of stalk chopping, such as too long maize stalk after chopping, and the low chopping pass rate of maize stalk, particularly when the amount of maize stalk was large, while the scarf skin of maize stalk was toughness. The shortcoming of maize stalk chopping directly determines the next seeding production, seed germination, and final crop yield. This paper aims to propose a novel chopping method, and thereby to design a double rollers type stalk chopping and retention device with different rotation speed and dynamic double support. The device mainly included the shell, supporting plate, suspension device, gearbox, transmission, chopping and collecting blade, shaft of chopping, collecting blade, blade shaft of slide-cutting supporting blade, and slide-cutting supporting blade. In operation, the chopping and collecting blade with anticlockwise rotation, firstly collected and chopped maize stalk in the field; then the maize stalk was chopped in dynamic support of side-cutting supporting blade with same rotation direction of chopping and collecting blade. A mechanical analysis of maize stalk was conducted under the effect of chopping and collecting blade, as well the slide-cutting supporting blade. The results showed that the rotation speed of chopping and collecting blade, and the slide-cutting angle of slide-cutting supporting blade were the main factors to affect the stalk chopping process. Furthermore, a motion analysis of chopping and collecting blade was carried out, including two L-type blades and a straight blade. The results revealed that the bend angle and length along the cutting-edge of L-type blade, and the rotation speed of chopping and collecting blade, were the main factors to affect the unpicking rate of maize stalk, and chopping pass rate, when the number of chopping and collecting blade and operation speed of device were fixed. In the slide-cutting supporting blade, the cutting-edge curvilinear equation was in the form of the logarithmic spiral equation. Moreover, the range of slide-cutting angle was 30º-60º, due to the slide-cutting angle can be more than frictional angle between maize stalk and slide-cutting supporting blade, according to slide-cutting principle. Importantly, the cutting edge of slide-cutting supporting blade with sawtooth was designed to increase the fraction of maize stalk and slide-cutting supporting blade. Prior to accurately coordinating between chopping and collecting blade, and side-cutting supporting blade, the rotating speed range of chopping and collecting blade was determined as 1 150 -2 500 r/min, to ensure the high stalk chopping pass rate. The rotation speed of slide-cutting supporting blade was one half that of chopping and collecting blade, to guarantee the speed of backward spread of chopped maize stalk. Simultaneously, the chopping and collecting blade, and side-cutting supporting blade, both were double helix arrangement to reduce machinery vibration, while increase machinery life. One device was installed 20 chopping and collecting blades, and 40 slide-cutting supporting blades. A quadratic rotation orthogonal combination test was used in the field research, to obtain the optimal structure parameters, where the chopping pass rate of maize stalk was set as test index. Some test factors were selected, including the cutting-edge bend angle of L-type blade (20º ≤γ≤60º), and cutting-edge length of L-type blade (30 mm ≤k≤60 mm), rotation speed of chopping and collecting blade (1200 r/min≤nY≤2 000 r/min), and slide-cutting angle of slide-cutting supporting blade (30°≤τ≤60°). The Design-Expert 8.0.6 software was applied to analyze the double factors interaction on stalk chopping pass rate, thereby to obtain the regression model between test factors and index. The primary and secondary factors that affect the maize stalk chopping pass rate were the rotation speed of chopping and collecting blade, the length of cutting-edge bend angle, the cutting-edge length of L-type blade, and the slide-cutting angle. In multiple objective optimization, the optimum ranges can be achieved, including the cutting-edge bend angle of L-type blade (41º≤γ≤57.64º), the cutting-edge length of L-type blade (41.7 mm≤k≤51.71 mm), the rotation speed of chopping and collecting blade (1 657.37 r/min≤nY≤1 889.97 r/min), and slide-cutting angle of slide-cutting supporting blade (36.55º ≤τ≤ 49.08º). In the field test, the rotation speed of chopping and collecting blade, the length of cutting-edge bend angle, and cutting-edge length of L-type blade, and slide-cutting angle were set as 1700 r/min, 40º, 45mm, and 45º, respectively. The field test results demonstrated that the maize stalk chopping pass rate was 92.58% under the optimal working parameters, while the error with the predictive value (93.96%) was less than 5%, indicating the reliable optimization of parameters. The finding can offer a sound reference to improve the chopping quality of maize stalk in the chopping and retention machine. [ABSTRACT FROM AUTHOR]